“New Perfect Engineers” Single Ferrule Fittings / Din 2353 Fittings is a three piece design consisting of a body portion, a coupling nut and a ferrule. During the assembly the nut is progressively tightened causing hardened ferrule to slide along the inner conical seat of the body and grip the tube. Tightening the nut, ring deforms due to 24 degree cone of fittings and bites into the steel tube, producing deep cut on the tube.

The cut is visible on the outer diameter of the tube. This cut on the tube acts as metallic interlock and makes the joint leak proof at high pressure and under vibration.