Immersion Research Thermo Hood
Here's what other sites are saying:
The Sea to Summit TPU Guide Map Cases are made from TPU (thermoplastic polyurethane), totally welded construction and a super strong Ziploc(R) closure to provide fully waterproof and dustproof performance. The PVC-free TPU material is strong, durable, flexible and resistant to UV and extreme cold - so it can be folded numerous times for pocket storage without cracking or discoloring. Designed with a detachable neck strap and corner anchor points for versatility.
Made out of .5 mil neoprene - warm and insulating. Low profile design fits right above ears. Designed to be worn under a helmet. Soft Lycra binding around the edges.