The perfect complement to our Timberland PRO® Pac Max 10" work boots, these heavyweight liners feature Mylar® zoned insulation for extreme warmth certified to -76 degrees Fahrenheit and our Anti-Fatigue Technology polyurethane footbeds that absorb shock and provide energy return for long days on your feet. Their breathable, moisture-wicking linings are made of ReBOTL™ fabric containing at least 50% recycled plastic with an antimicrobial treatment for odor control. Elastic goring allows for a customized fit, while cushioned, supportive EVA heel cups were added to eliminate heel slippage in the shells. Heel loops make it easier to pull them on or hang them up to air out.