I bought Black Diamond X4s this spring when I got a wicked deal on them, and I'm thrilled with the performance the cams give every time they're placed. During a three month trip we took this summer, me and my friends put them to the test on rock of all kind and in a wide range of weather conditions.
Hail, rain, and thunderstorms while in South Dakota and Wyoming. Dry sand and mud brick at Grand Junction, Moab, and City of Rocks. And Yosemite's hot, humid summer. Through that, all the funky placements and falls, the X4 cams held excellent in varieties of granite and sandstone. The cam lobes, Dyneema slings, and springs, basically every part of the cams, proved very durable through all that wear and tear.
Some of the features that really impressed me:
-The double and stacked axles give a very broad range, because of this, I'm less likely to make a sizing error.
-The larger X4's (.4, .5, and .75) head is 20% narrower then the C4. The smaller X4's (.1, .2, and .3) internal cam spring technology keeps the heads narrow, making pin scar placements possible.
-Aluminum beaded armor protects the single stem over sharp edges, horizontal placements, etc. without losing their great flexibility.
-Kevlar trigger wires on the lager sizes add to make these exceptionally durable cams.
-Dyneema sling are lightweight, tough, and brightly colored. Color code matches the C4's .3 through .75.
Aid climbing can really jank protection up. Being on 3 big walls, yes, they're a little bent but not more then expected from Clean Aid climbing. The X4s have been excellent, the lobes are very durable and the plastic around the clip-in point is nice and beefy.
Overall X4s place great in weird cracks, pods, pin scars, and even quite well in flared cracks. Black Diamond did a phenomenal job making a tough, sleek, easy to place cam. They also added easy to identify colors on the armored stem beads. Everything about the X4 is very complete and well made, not to mention just even looking awesome!