Stay warm and comfortable all season long with the Men's 'HEATTECH' Pile-Lined Sweatpants from UNIQLO. Engineered with HEATTECH technology, these sweatpants convert body moisture into heat while trapping warmth with a plush inner pile. The updated boa sweat fabric and single-piece construction offer a sleek, non-bulky silhouette that moves with you. Ideal for lounging or layering, they deliver effortless warmth and modern style in one essential piece.- 'HEATTECH' fabric with bio-warming and insulating properties.- Inner pile lining retains heat for lasting warmth.- Updated pile lining fabric sweat for a soft, cozy feel.- Single-piece front and back construction reduces bulk and stiffness.- Ribbed waistband and hems for a secure, heat-trapping fit.- Side and back pockets for everyday convenience.- Designed for both indoor comfort and outdoor versatility.Compare 3 Types of 'HEATTECH' Fabric:'HEATTECH'- Lightweight yet warm, ideal for everyday layering. - Recommended for 41 °F to 68 °F for mild winter days or cozy indoor wear. 'HEATTECH' Extra Warm- About 1.5× warmer than original 'HEATTECH', offering added insulation without bulk. - Perfect for colder days with recommended temperatures from 23 °F to 59 °F. 'HEATTECH' Ultra Warm - Our warmest option, approximately 2.25× warmer than original 'HEATTECH'. - Designed for more extreme cold with a recommended range of -4 °F to 50 °F. Men's HEATTECH Pile Lined Sweatpants with Bio-Warming Black Medium UNIQLO US