
Self-fastening and rejuvenating special profile with aggressive spiral nut. - 1 x 913.1291 - Spiral profile impact socket, 1/2", 17mm. - 1 x 913.1292 - Spiral profile impact socket, 1/2", 19mm. - 1 x 913.1293 - Spiral profile impact socket, 1/2", 21mm.