With the narrowest head of any cam on the market, the Black Diamond C3 is a great feat of engineering, resulting in a three-cam unit that fits, where nothing else does. This piece loves shallow horizontal placements, but isn’t great in vertical parallel-sided cracks, flaring cracks orpin scars.
The Black Diamond C3 is a five-piece set of very small cams that you might hope you’ll never have to place, but when you do, you’ll be glad you have these three-cam units. The C3 has a unique stem design that eliminates the protruding U-stem found on the Metolius TCU and therefore achieves the most narrow head of any cam on the market. However, the stem is very stiff, making the cam prone to walking, especially in vertical cracks. These cams work best in shallow, horizontal pods where nothing else will work and there’s no opportunity for the cam to walk itself out of position. Definitely not for use in areas with flaring cracks or pin scars.
Value The C3 are some of the most expensive cams on the market. Their durability, and unique ability to fit where nothing else works, justifies that expense if you are in the market for a great three-cam unit.
Ergonomics The C3 has a really stiff trigger pull, that we didn’t love right out of the gate, but over time got used to it. Still, it’s hard to get a feel for finding that proper placement with such a stiff trigger pull. Beyond that, the cam fits in your hand perfectly.
Design / Weight The C3’s narrow head fits where nothing else will, and has proven to be a (literal) lifesaver in tough situations on granite and conglomerate. However, the bulky stem can often interfere with placements, especially vertical placements. This is why we recommend them in areas with horizontal pods and pockets (the Gunks, Eldorado Canyon, etc.) as well as big-wall aid climbing on El Capitan.
Resistance to Walking The combination of a stiff stem with the three-cam head, make the C3 a cam that likes to move and walk around. This feature could’ve been improved if the sling was slightly longer, to allow use with a single carabiner. Otherwise, we recommend clipping a longer sling to help with walking.
(Learn more about climbings cams and how to choose the right one, here.)