For driving rethreading taps from M1.5 to M14. Sockets have special square profile to fit the tap shanks. For use with 3/8″D & 1/4″D ratchets, ideal for restricted access where a T-handle tap holder will not reach. 6 x 1/4″D magnetic sockets (socket number to square size): # 1 (2.8mm), # 2 (3.4mm), #3 (4mm), #3.5 (4.5mm), #4 (4.6mm), #4.5 (5.4mm); length: 32mm. 4 x 3/8″D magnetic sockets (socket number to square size): #5 (6.4mm), #6 (7.3mm), #7 (7mm), #8 (8.4mm); length: 40mm.