Durafit Seat Covers, C1100-X7, 2003-2007 Chevy Silverado and GMC Sierra, Work Truck Seat Covers, Front 40/20/40 Split Seat with Manual Controls and Without Console, in Gray, Twill Fabric 2003-2007 Chevy Silverado and GMC Sierra Work Truck Seat Covers. Front 40/20/40 Split Seat. Manual Controls and Without Console. Integrated Seat Belts on top of the seat. Excellent for work truck, snap and slip on covers with easy installation that sits firm on the seats. These are put on car seat covers. Made in Gray Automotive Twill Twill is a durable flat woven material often used by auto manufacturers. A polyester based fabric, twill is very strong and is Teflon and UV treated to withstand stains and fading. We use US made automotive grade twill which is designed for use in vehicles.