Big Agnes Insulated Q-Core Sleeping Pad X-Static synthetic insulation enhanced with silver filament to increase thermodynamic, antimicrobial and anti-odor properties Durable, lightweight ripstop nylon fabric on top and bottom Internal polyurethane-coating enhances durability and prevents air leaks Alternating I-beam construction creates a smooth, consistent feel and eliminates cold spots Large outside air chambers cradle you in the middle of the pad