In the case of a knock-in peg with a shaft which is provided with a continuous longitudinal groove and a preferably conical tip and has a hitting head which forms a structural unit with the shank, it is provided according to the invention that the structural unit consists of a polyamide which has an elongation at break from dry to wet of 70 to 250, a tensile modulus of elasticity from dry to wet of about 80 to 55, an (Izod) notched impact strength from dry to wet of 48 to 270 and a Shore hardness from dry to wet of about 82 to 77 and the hitting head has a disc-shaped flange, the hitting surface taking the form of a circular disc surface interrupted by the groove.
