This padlock shackle has been designed using a hardened steel material. There are 3 different models available under the 40F range, with the shackle clearance being the main difference, The FD40F (22mm), the FD42F (50mm), FD43F (75mm) & finally FD40F/TP (22mm). The body itself is made using solid brass. Overall this is a great budget padlock that..