A nucleated propylene polymer composition made from or containing: A) a propylene homopolymer; B) a copolymer of propylene with ethylene derived units; the nucleated composition having a fraction soluble in xylene at 25° C. between 9.0 and 21.0 wt %, an intrinsic viscosity of the fraction soluble in xylene at 25° C. between 1.0 and 1.9 dl/g, a total melt flow rate between 1.5 and 5 g/10 min and the value of the relation (I): 22.5+0.2*MFR−1.2*Xs+0.2*IV  (I) is higher than 5.9; wherein MFR is the melt flow rate of the nucleated composition; IV is the intrinsic viscosity of the fraction soluble in xylene at 25° C.; and Xs is the fraction soluble in xylene at 25° C., the amount of A+B is equal to 100 wt %, and the nucleating agent is selected from the group consisting of aromatic or aliphatic carboxylic acids, aromatic metal phosphates, sorbitol derivatives and talc.