Coupled with their zip off/on base layers, its a game changer. Climb with the base layer off and the zips open, stay cool. Get to a spot where you are going to sit, and zip on the base layer without having to take your boots off.I have Kuiu Attack and Tiburon pants. The hip zip is about 8" long on both sides. I live in western Colorado where climbing 1000'-200' vertical feet or more is common during a hunt and I'm a sweat hog. For 'active' hunting situations it's extremely helpful.