The Union Hercules padlock features a robust concealed shackle which slides vertically through a staple hole making direct attack impossible. The shackle is unsprung and the key is retained in the lock when the padlock is unlocked. This padlock is made from hardened, forged steel and the shackle is hardened steel. It is anti drill, anti saw, force resistant, anti pick and torque resistant. Furthermore, it is also corrosion resistant thereby making it ideal for external use. The Union Hercules padlock is available in either AVA 10 disc locking mechanism and is supplied with 3 keys.