i bought the klim covert to use with my motocross helmet and it was useless. it doesn't cover your nose at all. you can kinda cover your mouth and pull it up over the tip of your nose but it has no vents there so your breathing through material. and it still doesn't pull up far enough to go up under your goggles.
i ended up getting a neoprene and fleece balaclava that had a nose vent and mouth vent and goes all the way up the bridge of my nose. works perfect!
i recently got a full face helmet for VERY cold weather and tried the klim under that and my chin got really cold but that was like 5 or 10 below zero!
its a bummer as the thing was 50 bucks and really is useless.....for me atleast. ive got a kinda funky shaped head tho....i guess in the helmet world they call my profile a "long oval"