The Coilhose Pneumatics 5-in-1 Safety Exhaust Coupler, No. 150use, is designed to remain connected to the plug until the downstream air is completely bled off, reducing the possibility of injury to nearby personnel or damage to surrounding equipment from a whipping hose that was disconnected while pressurized air was still in the line. Although not recommended for use directly connected to high-impact tools, the coupler eliminate the guess work or inconvenience of matching interchanges.