The set contains the most commonly used bits and sockets for installers of ventilation systems. The bit sockets are fitted with a spring-loaded ball that holds the bolt at the top. The bit holder has a quick-lock function.Contains1 piece of each Tx 10,15,20,25,30 1 piece of each PZ 1,2,3 1 piece of each PH 1,2,3 1 piece of each slot 3 & 5 mm 2 pieces of each robertson 1,2.3 1 piece of each bolt bit 27 mm 8 mm 1/4" 1 piece of bit holder quick-lock and magnet