The Heatgen™ technology in these thermal vests makes for an insulating yet lightweight base layer. Pack of two, both in a regular fit with a crew neck and short sleeves. Flexifit™ fabric made with Lycra® for 360 degree stretch and enhanced comfort. Moisture-wicking properties for all-day freshness. Super soft seams and heat-sealed labels ensure a gentle feel against your skin. Made with sustainably sourced viscose. All of the cotton for our clothing is sustainably sourced and always will be.