Item duplication. 1  Step 1. Have the block you want to duplicate in front of you. ( 2 Examples: Diamond, Gold, or Iron.). 3  Step 2. 4  Now you might want to have a Iron pickaxe or Diamond pickaxe. 5  Step 3. Use you'r pickaxe to quickly mine it.
Heavy Duty/Industrial. A backdraft damper is an isolation damper allowing air in one direction only. Greenheck's HB damper series is designed to prevent back flow at static pressures and velocities up to 20 in. wg and 6400 fpm, respectively.
Tjernlund BD-14 Backdraft Damper, 14 Duct, Spring Loaded. Backdraft damper with galvanized steel collar and lightweight aluminum damper blades. Spring loaded for positive closure against interior gasket. Product Features:14 spring loaded back draft damper.