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A4-816, Version A
A4-816, Version B
A1-811
A4-816 L
A7 Micro
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| A4-816, Version A | A4-816, Version B |
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| A1-811 | A4-816 L | A7 Micro |
The numbering for these ascenders may seem confusing - it is. The best explanation that I can offer is that the A1-811 was probably not numbered correctly when I bought mine (1994), and should have been the A4-816.
Boris Rogelja founded Single Rope Technique Equipment (SRTE) in 1980. Capital Safety Group acquired SRTE in 2011 and their devices started showing DBI-SALA, Capital Safety, and/or Rollgliss™ markings. Some of these continued to show SRTE markings, and some did not. There does not appear to be a specific date when the markings disappeared. Different devices removed the SRTE logo at different times. 3M acquired the Capital Safety Group in 2015 and the Single Rope Technique Equipment markings disappeared completely. Since the device designs and construction retained continuity while the branding changed, I see no reason to put the different brands on separate pages.
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[ Top | A4-816, Version B | A1-811 | A4-816 L | A7 Micro | Return to E.C. Ascenders ]
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| Front View: Closed | Rear View: Closed |
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| Front View: Open for Rigging | Rear View: Open for Rigging |
I acquired my Single Rope Technique Equipment A4-816, Version A from Single Rope Technique Equipment in 1989. I acquired another in 2017 as part of Bob Thrun’s collection.
The Single Rope Technique Equipment A4-816 is 118 mm. tall, 81 mm. wide, 46 mm. thick, and weighs 279 g. The body is extruded aluminum allow painted yellow. The attachment holes are 19 mm. in diameter. The rope channel is 18 mm. wide. The cam radius increases from 42 to 62 mm. over an angle of 45°, giving a 27° cam angle. The tooth pattern is (4.5)^3,(4.3)^2(4). The cam safety is milled from aluminum, anodized, and hinged from the bottom of the cam.
The body behind the cam is stamped "S.R.T.," "AUSTRALIA," and "EQUIP." There is a kangaroo cast into each side of the cam.
The A4 816 is designed to be a chest ascender for the Frog System. The body is milled from an aluminum extrusion that sets the attachment holes 45 degrees to the plane of the cam motion. This works, but leaves a ridge that sometimes digs into the chest. I find that the Kong-Bonaiti Cam-Clean or the Petzl Croll are somewhat more comfortable. The frame is rugged to the point of overkill, as one expects from an SRT ascender.
The cam is well made and the teeth are nicely formed. The safety
doubles as a hold-open catch for the cam.
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[ Top | A4-816, Version A | A1-811 | A4-816 L | A7 Micro | Return to E.C. Ascenders ]
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| Front View: Closed | Rear View: Closed |
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| Front View: Open for Rigging | Rear View: Open for Rigging |
I acquired my Single Rope Technique Equipment A4-816, Version B in 2017 as part of Bob Thrun’s collection.
The Single Rope Technique Equipment A4-816, Version B is 115 mm. tall, 80 mm. wide, 43 mm. thick, and weighs 292 g. The rope channel is 18 mm. wide. The cam radius increases from 42 to 62 mm. over an angle of 45°, giving a 27° cam angle. The tooth pattern is (4.5)^3,(4.3)^2(4).
The Single Rope Technique Equipment A4-816 is 115 mm. tall, 80 mm. wide, 43 mm. thick, and weighs 292 g. The body is extruded aluminum allow painted yellow. The attachment holes are 19 mm. in diameter. The rope channel is 18 mm. wide. The cam radius increases from 42 to 62 mm. over an angle of 45°, giving a 27° cam angle. The tooth pattern is (4.5)^3,(4.3)^2(4). The cam safety is stamped stainless steel with a turned knob attached, and hinged from the bottom of the cam.
The body behind the cam is stamped "S.R.T.," "AUSTRALIA," and "EQUIP." There is a kangaroo and an up-pointing arrow labeled "UP" cast into each side of the cam.
I prefer the new safety, but in use, the difference between the two is minor.
[ Top | A4-816, Version A | A4-816, Version B | A4-816 L | A7 Micro | Return to E.C. Ascenders ]
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| Front View: Closed | Rear View: Closed |
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| Front View: Open for Rigging | Rear View: Open for Rigging |
I acquired my Single Rope Technique Equipment A1 811 from Inner Mountain Outfitters at the 1994 Old Timers Reunion. I acquired another in 2017 as part of Bob Thrun’s collection.
The Single Rope Technique Equipment A1 811 is 113 mm. tall, 76 mm. wide, 39 mm. thick, and weighs 225 g. The body is milled from an aluminum alloy extrusion and then anodized. The rope channel is 14 mm. wide. The cam radius increases from 43 to 61 mm. over an angle of 41°, giving a 25° cam angle. The tooth pattern is (3.4)^2(5.4)^2(3.4)^2(F). The cam safety is stamped stainless steel with a turned knob attached, and hinged from the bottom of the cam.
The rear of the body is stamped with "AUSTRALIA," "SRT" inside a map of Australia, and "PATENTED." The cam has a raised up-pointing arrow labeled "UP" in raised letters, and "S R T" in raised letters.
The A1-811 is the "Explorer" series Version of the A4-816. There are minor differences in how the frame is milled, but these make no functional difference that I can see. The cam is slightly different, and the cam safety is made out of a heavy stamping with a turned pin attached, while the A4-816 cam is a cut extrusion.
I consider these two ascenders
to be interchangeable. Neither has a clear advantage over the
other.
[ Top | A4-816, Version A | A4-816, Version B | A1-811 | A7 Micro | Return to E.C. Ascenders ]
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| Front View: Closed | Rear View: Closed |
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| Front View: Open for Rigging | Rear View: Open for Rigging |
I acquired my Single Rope Technique Equipment A4 816 L from Single Rope Technique Equipment in 2000.
The Single Rope Technique Equipment A4 816 L is 116 mm. tall, 80 mm. wide, 43 mm. thick, and weighs 292 g. The rope channel is 18 mm. wide. The cam radius increases from 41 to 61 mm. over an angle of 41°, giving a 29° cam angle. The tooth pattern is (3.4)^2(5.4)^2(3.4)^2(F). The cam safety is stamped stainless steel with a turned knob attached, and hinged from the bottom of the cam.
The rear of the body is stamped with "S.R.T.," "AUSTRALIA, "EQUIP." and "19925201." The cam has a raised up-pointing arrow labeled "UP" in raised letters, and "S R T" in raised letters.
The SRT catalog lists this as the A4-816 R, but the receipt
listed it as an A4-816 L. I think that the latter makes more sense,
but it doesn't really matter what you call it - its a larger Version
of the A1-811 (now called the A4-811 R, or is it L?) that can
handle 8 to 16 mm. ropes for the "bigger
is better" crowd.
[ Top | A4-816, Version A | A4-816, Version B | A1-811 | A4-816 L | Return to E.C. Ascenders ]
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| Front View: Closed | Rear View: Closed |
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| Front View: Open for Rigging | Rear View: Open for Rigging |
I acquired my Single Rope Technique Equipment/Rollgliss/DBI Sala Rescue Explorer from ropeandrescue.com in 2013. I acquired two more in 2017 as part of Bob Thrun’s collection, and a fourth from Lance Swartwout in 2019.
This ascender
is is 102 mm. tall, 65 mm. wide, 24 mm. thick, and weighs 178 g.
The shell is milled from a custom aluminum extrusion and then anodized gold.
The shell body is 6.5 mm. thick. The rope groove
is 14.4 mm. in diameter and U shaped. The cam mounting groove
is rectangular. The upper attachment slot is 45.1 mm. wide and 6.1 mm. high. The inside of the shell above the slot is relieved 1.15 mm. to provide clearance for a webbing attachment (45 mm. webbing fits nicely). The lower attachment
point is milled "around the corner" to leave a 15.4 mm. wide, 15 mm. high hole.
The cam is a plated skeletonized, reinforced stainless steel casting. The cam radius increases from 35 to 49 mm. over an angle of 48°, giving a 22° cam angle. The tooth pattern is (4.5)^3,(4.3)^2(4). The cam, cam spring, and a cam housing are mounted on a 6.4 mm. semi-tubular rivet. The cam pivot is centered 47 mm. from the inside of the rope groove. The cam housing is a piece of thin sheet metal bent to cover the top of the cam channel and serve as a spacer along the sides of the cam. The top of the housing is indented; this limits cam closing so that the teeth do not hit the inside of the rope channel. There is a small safety attached to the bottom of the cam. The normal action of the spring holds the safety against the cam. When the cam is opened, the shell interferes with the safety bar, thus preventing opening the cam. If the safety bar is moved away from the cam (opposing the spring), it will clear the shell and the cam will open. At full open the safety can be released and the spring will hold the safety against the back of the shell. This provides a means of locking the cam open. A pin on the safety bar (shaped like the frustum of a cone) assists in operating the safety mechanism.
The front of the rope channel is printed with "CAPITAL SAFETY," the DBI-SALA logo, "www.capitalsafety.com," an arrow pointing up, and "UP." The rear is printed with "CAPITAL SAFETY," the DBI-SALA logo, "www.capitalsafety.com," "Rollgliss®," "8700522," "A7 Micro," the SRTE logo, "MAX AT CAM 800kg," a book-with-an-"i" icon, "Rope ¥ 10.5≤ Ø ≤ 13mm, "CE 2056," "EN 12278," "AS/NZS 4488," a danger icon, "Made under a quality scheme certified by SAI GLOBAL," "Lic SMKH25365," "MEETS NFPA 1983 (2012 ED)T," "WARNING," "PROPER TRAINING IS ESSENTIAL," the SAI GLobal certified product icon, " D.O.M. Jul 2013," and "SERIAL # 231839408."
This is a left-hand ascender intended to be used as a chest ascender. The upper webbing attachment is specialized, and might be the best option in some circumstances, while inappropriate in others.
When used with a loose harness, the back of the ascender has enough reading material to hold one’s interest during the longest of climbs.
[ Top | A4-816, Version A | A4-816, Version B | A1-811 | A4-816 L | A7 Micro ]
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