Padlock with an aperture on the inside to engulf the staple of the padbar. The toughened steel vertical sliding shackle, which is completely concealed when locked, passes through the staple hole making direct attack impossible. Suitable for use with Chubb 7B018 and 7B020. Locking is provided by a 10 disc Ava mechanism giving many million key variations. Protected against drill attack, the key can only be removed when the padlock is secured.