This is a mini coupler (female side) and plug (male side) made out of stainless steel with 1/8" pipe threads from Power Tank. We use these in our nitrogen equipment like our N2 Power Filler (NIT-0200) and Shock Inflator tools (SIG-5600). They are made for high pressure applications up to 3000 psi and the small size is great for running smaller air lines. Available as a male plug, female coupler, or a matched pair.
Note: There are two versions of the male plug. One with and one without a check valve. The one without is an open plug and allows air to pass through in both directions. The check valve limits air movement to a single direction. The check valve plug is a direct replacement on our N2 bottle valve.