Reusable Hose Barb - 1/4" Body Coupler X 1/4" ID - 5/8" OD M Style Air Fitting

Foster Brand

SB7-3
1/4" Industrial Coupler for 1/4"ID X 5/8" OD hose
1 pc

This is the most common Coupler type.
Here are some common names associated with it.

Industrial
M Style
I/M
I
Mil Spec