Front	Rear

Technical Details

I acquired my NAT on eBay from Jack Patterson in 2014.

The NAT is forged from aluminum alloy and then soft anodized. Mine is 140 mm. tall, 73 mm. wide, and 12 mm. thick. The rope hole is 49 mm. high and 50 mm. wide. The top center thickness is 12 mm. The shaft length and width are 43 mm. and 24 mm., respectively. The eye measures 24 mm. by 24 mm. My eight weighs 101 g.

One side is printed with "Y N-505," "NAT," "12," and "TTV." The rear of the shaft has a raised strength test icon (not a rigging illustration!) with "kN▲35" above and "▼" below.

Comments

The NAT is a full-size forged eight with a flat shaft. The following eights are similar in design, but their markings vary:

Image Eight I Climb (元鴻興有限公司) #631 Kong Classic, Version A Kong Classic, Version B	Image Eight Kong Classic, Version C 40th Anniversary Edition NAT Rock Empire, Version A	Image Eight Rock Empire, Version B Treehog	Image Eight U. S. Rigging Supply USR-835-A Yoke, Version B

Each of these eights is 139-140 mm. tall and 72-73 mm. wide. Their weights fall in the 107±6 g. range. These are normal manufacturing variations that have no practical significance. They are smaller and lighter than Standard, Full Size, Forged Eights, but the difference is not enough to make large changes in their performance.

The shafts on these eights are rather flat, which helps reduce weight. The depressions help avoid the slight grabbiness I find on the Full Size, Forged Eights with Flat Shafts. It also reduces the contact area for dissipating heat, but in the range of drops that I use eights (usually not more than 15 m. caving), this is not noticeable.

Each of them has an irrelevant strength test icon with a strength rating forged into one side. This marketing gimmick is rather silly. The rigging shown for the strength rating is not how an eight is normally used, so it is misleading. It is not the accepted method for measutring strength of an eight. The accepted and more realistic strength test arrangement is shown in EN 15151-2:2012, figure 3. The strength listed on these eights greatly exceeds the 7 kN. requirement in the standard for what is needed for safe use. This leaves fair margin for reasonable wear. Paying any attention to the difference between 25 kN and 35 kN ratings for normal use is absurd.

None of these eights have slots for sticht-type belaying, and their round eyes are not designed for that purpose.

Although similar, these eights are not identical, and close inspection will reveal some minor differences in their shapes. None of these affect their performance to any noticeable degree.