Volume Damper for Spiral Duct (DT) by Eastern Sheet Metal $55.00 6" - $55.00 8" - $65.00 6" 8" Duct Size 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Model: DT Dampers come standard with:• 3/8" locking handle• Nylon bushings• Insulation stand off