RAB says about the Phantom Pants

When the weather turns, the Phantom Pants offer a second skin defence. Offering feather weight protection and the ultimate packability, you’ll take them every time you run. Built with waterproof and breathable 7D, 2.5-layer Pertex® Shield and ultralight taped seams, they’re quiet to wear, soft to touch and ultra-packable, compressing down into a palm sized stuff sack. The Phantom Pants offer an unrestricted range of movement with pre-curved knees optimised for running, stretch, a slim-fit, and not an ounce of unnecessary fabric. The waistband is part elasticated with a drawcord adjuster to perfect the fit and the lower leg hem has a snap fastener with hook and loop, for easy on/off pull over trail shoes.