Copperhead Climbing Nuts were originally developed as chocks for clean climbers, which is why I included them here. Nowadays they are primarily used as bashies for aid climbing on harder nail-ups where they are artfully pounded into thin seams to provide marginal bodyweight support. These placements cannot be trusted to hold a fall — they rarely will.
Copperhead data tables in my Forrest Mountaineering Ltd. catalogs from 1974 to 1983 list cable sizes of 3/32", 3/32", 1/8", 5/32" and 3/16" for Copperhead sizes #1 through #5, respectively. I have an earlier (undated) Forrest brochure that listed 1/16" for the #1's cable. That version was much weaker, rated at only 480 lbs (2.1 kN) under ideal laboratory conditions. The #1 (either version) and #2 Copperheads should only be trusted for direct aid.
Forrest discontinued making copperheads long ago, but Fish and others continue making them to support the demand of aid climbers. Original Forrest Copperheads are difficult to find and even more difficult to verify, as there are no distinct features that make specific brand identification practical.
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↑ 414: Forrest Copperhead Climbing Nut #1–S: 13x4 mm.
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↑ 326: Forrest Copperhead Climbing Nut #3: 18x9 mm.
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↑ 333: Forrest Copperhead Climbing Nut #3–S: 18x9 mm.
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↑ 412: Forrest Copperhead Climbing Nut #4: 22x10 mm.
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↑ 413: Forrest Copperhead Climbing Nut #4–S: 22x10 mm.
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↑ Set 158-160: Forrest Arrowheads #1–#2
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↑ 158: Forrest Arrowhead #1: 6 mm.
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↑ 159: Forrest Arrowhead #2: 7 mm.
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↑ 160: Forrest Arrowhead #3: 10 mm.
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↑ 014: Forrest Plastic Foxhead #3: 24, 35 mm.
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↑ Set 014-015: Forrest Plastic vs. Aluminum Wired Foxhead #3
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↑ Set 161-162,015: Forrest Wired Foxheads #1–#3
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↑ 161: Forrest Wired Foxhead #1: 18, 24 mm.
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↑ 162: Forrest Wired Foxhead #1: 19, 24 mm.
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↑ 163: Forrest Wired Foxhead #2: 22, 30 mm.
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↑ 015: Forrest Wired Foxhead #3: 24, 35 mm.
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↑ 164: Forrest Short Wired Foxhead #1–S: 19, 24 mm.
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↑ 165: Forrest Short Wired Foxhead #3–S: 24, 35 mm.
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↑ 165: Forrest Short Wired Foxheads #3–S: 24, 35 mm.
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↑ Set 294-294: Forrest Titons T3–T5, #6–#9
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↑ 122: Forrest Titon T3: 18, 25 mm.
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↑ 296: Forrest Titon T4: 22, 31 mm.
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↑ 121: Forrest Titon T5: 25, 34 mm.
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↑ 120: Forrest Titon #6: 31, 44 mm.
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↑ 297: Forrest Titon #6: 31, 43 mm.
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↑ 118: Forrest Titon #7: 37, 54 mm.
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↑ 119: Forrest Titon #7: 37, 54 mm.
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↑ 324: Forrest Titon #8: 50, 70 mm.
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↑ 298: Forrest Titon #9: 63, 83 mm.
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↑ 117: Forrest Titon #9: 50, 79 mm.
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↑ Set 109-116: Forrest Titons #10–#17
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↑ 109: Forrest Titon #10: 50, 89 mm.
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↑ 110: Forrest Titon #11: 50, 99 mm.
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↑ 111: Forrest Titon #12: 50, 114 mm.
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↑ 112: Forrest Titon #13: 50, 126 mm.
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↑ 113: Forrest Titon #14: 50, 140 mm.
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↑ 114: Forrest Titon #15: 50, 152 mm.
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↑ 115: Forrest Titon #16: 50, 165 mm.
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↑ 116: Forrest Titon #17: 50, 177 mm.