This is Atlas Copco part number 3121503800 adapter, stocked at Crowder Supply as AC-3121503800. It makes the air or hydraulic connection to the tool. Thread and sealing-face condition here is the difference between full pressure at the tool and a slow leak nobody notices.

If you are working from a machine rather than a part number, start at the full diagram library, or send us the model and serial and we will match it. Machines themselves are on the Atlas Copco tool range. Ships from our Denver warehouse; in-stock parts ordered by 4 PM ET go out the same day.

• Part number: 3121503800
• Manufacturer: Atlas Copco
• Crowder SKU: AC-3121503800