the device of the invention comprises a clamp and a ring adapted to be screwed to a connector to form a stress relief removably attached to the rear of the connector . in accordance with the invention , the clamp has two parts : a rear part forming a receptacle and a front part which is open , having a &# 34 ; c &# 34 ; shape . the material of the clamp is a composite material having elastic properties . by compressing it , the branches of the &# 34 ; c &# 34 ; can be moved closer together and the clamp inserted in or removed from the ring . the clamp also includes pegs providing insertion abutments , preventing withdrawal of the ring . the clamp can be straight or angled .