Brass quick coupler with pipe thread R1/8". The couplers are used for air engineering and in 3D printing serve to guide the filament in the bowden.
Use the Teflon ring to easily insert and remove the tube.
Suitable for dimensions outer D = 4 mm / inner d = 2 mm
These couplers are used within copies of E3D HotEnds and many other hotends
Pneumatic connector PC4-01 for tube 4 mm * 2 mm
Direct screw connection, thread R1/8", Teflon ring, external hexagon D 10 mm
The product image is illustrative - the plastic ring may have a different color.