The Black Diamond X4 is a small-cam set that achieves tremendous stability and range in a four-cam head that is actually narrower than most three-cam heads, including the Metolius TCU. The X4 set contains six sizes, but it’s really only the smallest four sizes that shine. Among small cams in the Black Diamond family, we prefer the X4 to the C3. Compared to Metolius Master Cams and Aliens, the X4 is also a bit heavier and more expensive.
Pin scars, thin cracks and narrow pockets absolutely swallow up the Black Diamond X4 Camalots. Each individual unit’s range is incredible considering its size, making for a reliable cam that fits everywhere and would be difficult to get stuck.
The X4’s come in six sizes, but it’s really only the smallest four sizes that we recommend as the two largest pieces in the set—the #.75 and #0.5—have virtually identical counterparts in the Black Diamond C4 set; and on those two sizes we prefer the C4 to the X4, mostly due to familiarity.
The real deal behind the X4, though, is its narrow head. The X4 just fits where other cams don’t. When you place it, it inspires confidence.
Ounce for ounce, the X4 is slightly heavier than other similar cams; however, as the cams are small and therefore already light, this isn’t a huge deal. Over all, the difference in weight between one set and another might be the equivalent of a carabiner or two.
Value The X4 costs slightly more than other cams such as Aliens and Metolius Master Cams, both of which are extremely solid offerings at a better price.
Ergonomics The X4 fits into your hand really well. The thumb loop and trigger bar are well spaced and make it easy to grab and place one-handed. Also the stem’s stiffness contribute to the ease of operation—i.e., the cam doesn’t easily “buckle” when placing it.
Design / Weight The X4 is between 0.2 and 0.5 ounces heavier than other cams of comparable sizes. It’s also worth noting that the X4 has no cam stops, so it can’t be placed as a passive piece.
Resistance to Walking The flexible single stem achieves a great balance between rigidity for easy placement and flexibility that prevents cam walking. With great holding power, these cams stay put no matter how much the rope pulls on them.
(Learn more about climbings cams and how to choose the right one, here.)