Rothco Thermal Knit Underwear Bottoms - Men's 3XL Black. The thermal underwear features an elastic waistband and ankles for a superior fit. Stay cold weather ready with Rothco''s Thermal Underwear tops which are also available at Rothco.com.' Specifications for Rothco Thermal Knit Underwear Bottoms: Manufacturer: Rothco Gender: Male Age Group: Adults Application: Active Cold Weather Outdoor Fabric/Material: 55percent Cotton/ 45percent Polyester Fastener/Closure Type: Elastic Waistband Apparel Fit: Snug Seasonal/Temperature Use: Cold Weather Features of Rothco Thermal Knit Underwear Bottoms Material: Polyester Material Specs: 55percent cotton 45percentpolyester Weather: Cold Weather Package Contents: Rothco Thermal Knit Underwear Bottoms Rothco 63646-Black-3XL: Thermal Knit Underwear Bottoms - Men's 3XL Black