Passive climbing pro

Passive Protection Choices

Tapered wedges and camming chocks make up the quiver of climbing gear known as passive protection or "pro" for short. They are commonly referred to as nuts, stoppers, tricams and hexes.

These variously shaped chunks of aluminum and aluminum alloy all share one characteristic—they have no moving parts. They are either attached to a wire cable, a loop of accessory cord or a sewn webbing sling.


As their name implies, these aluminum pieces are larger at one end and become smaller at the other. They are designed to slide into tapering cracks and wedge into the narrowest part. Tapers typically work the best in narrow-to medium-width cracks. The best placement occurs when the most surface area of the chock is in contact with the rock. Because of their wedge shape, they are not as well suited to parallel-sided cracks.

Expert Tip: “The type of rock on which you most frequently climb should determine the material from which your tapers are made. Brass nuts are best suited for fragile rock like sandstone. They may shear out of harder rock like granite. However, they can be used to accommodate static forces in aid climbing on most rock. Steel and aluminum-alloy are most suitable in granite, but may shear out of softer rock.” –Heidi Pesterfield, author of Traditional Lead Climbing.

Tapers typically have slightly curved faces. One side is convex and the opposite is concave. The convex side locks against the two contact points of the concave side, creating a stable triangulation of forces. Some tapers have cutout areas for better fit in uneven rock surfaces.

Micro Nuts

Micro nuts are a smaller type of taper. They are reserved for thin cracks or old piton scars when no other protection will fit. They can be as much as 75% smaller than most standard tapers.

Camming Chocks

These have no moving parts. Unlike tapers, though, camming chocks have the ability to rock or twist into a "locked" position in a crack or pocket. They are useful in cracks too large or straight-sided for tapers to fit well. Camming chocks are commonly placed in parallel-sided cracks, round pockets and horizontal cracks.

Tri cams are rounded on one side and come to a point on the other. They can be placed directly into cracks (like tapers) or with the sling running alongside the curved edge, cammed into place. Force applied to the sling rocks the curved edge and forces the point into the rock. Placing tricams takes practice, but once the technique is mastered they are very useful.

Hexentrics are asymmetrical, 6-sided tubes. Like tapers, they can be placed directly into narrowing cracks. In straight-sided cracks they can also be rotated into place. Downward force on the wire or sling rotates the hex and wedges it tightly in the crack.

Why Passive Pro?

Why buy passive protection, though, when spring loaded camming devices (SLCDs) are so secure and easy to place? There are actually several reasons:

  • When placed in flaring cracks (cracks that get increasingly wider), SLCDs have been known to "walk" themselves out. Hexentrics are often a more secure option.
  • A rack with a full set of tapers or hexes is not only lighter than one with the same number of spring-loaded cams, but it's less bulky. Plus, the pieces are less likely to get tangled.
  • Occasionally a climber is forced to leave behind a piece or 2 of pro in order to back off a climb or to do an unexpected rappel. Most would rather leave a couple of $10 stoppers than a $70 spring-loaded camming device.

That's not to say that one should only carry passive protection. Spring-loaded camming devices have broader working ranges than tapers or hexes, and they fit in pockets and parallel cracks more readily than most passive pro.

The most versatile racks have some of each—passive and spring-loaded protection—to handle a variety of routes and types of rock. Practice and experimentation will help you decide on the best type of protection for the formations in your favorite climbing areas.