This package contains 4 PC4-01 NPT Straight-Thru Bowden Fittings.

NPT stands for National Pipe Thread and is an American standard thread.

01 threading is 1/8 inch diameter, similar to M10 but with a slight taper.

These fittings have a 4.1mm rear opening to allow the tubing to pass all the way through.

0.9mm pitch.

For 1.75mm filaments.