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Adjustable and Dynamic Cow's Tails

Adjustable cow's tails allow one to change the length of the cow's tail easily.

The problem with a standard cow's tail is that if one falls from above the anchor, the resulting fall factor can be quite high. This is especially true for via ferrata, where fall factors of 5 or 10 or even more are possible. Dynamic cow's tails incorporate a shock absorber of some form so that the forces generated in such falls are greatly reduced, hopefully to within human tolerance. The ones listed here are commercially produced, and except for the gear4rocks and Kong Slyde, include their own sling rope. These should only be used in the situations recommended by the manufacturer. Most of the anchor brakes can also be used to make dynamic cow's tails, if the manufacturer endorses such use.


The weights in the following table are for the entire kit, unless otherwise noted. The dimensions are for the brake plate.

Image ID Device Description Acquired Weight Height Width Thickness Std. volume
Eiselin Sport 708 Eiselin Sport Forged Al, unfinished, 5-12 mm. rope holes, oval eye Eiselin Sport, 1997 59
(plate only)
81 48 10 39
Kong Doble Longe (Slyde) 698
Kong Doble Longe (Slyde) Milled Al plate, soft anodized, rope hole & slot, eye.
  • Inner Mountain Outfitters
  • Bob Thrun Collection, 2017
(plate only)
63 49 10 31
gear4rocks 1697 gear4rocks Milled plate, painted, 2 slot gear4rocks, 2010 49 68 40 10 27
Mammut Klettersteigset 785 Mammut Klettersteigset Forged Al, Anodized, 5 12 mm. rope holes, L-shaped eye Inner Mountain Outfitters, 2003 437 90 49 9 40
Petzl Zyper 703 Petzl Zyper Forged Al, unfinished, rope hole, V slot Inner Mountain Outfitters, 1997 294
109 40 14 61
Simond Aerofrein 786 Simond Aerofrein Milled Al, soft anodized, 4 10 mm. & 2 16 mm. rope holes, 15 mm. eye Inner Mountain Outfitters, 2003 576 87 46 8 32