A key blank comprises a shaft and a head connected to the shaft, the shaft including first and second surface that are oppositely facing, wherein the surfaces are configured to include combination elements to operate a lock and a pair of coaxial operating elements, wherein one element of the pair is operative from the first surface of the shaft and the other element of the pair is operative from the second surface of the shaft, and wherein at least one of the operative elements is a resilient element mounted inside a bore provided in the shaft, wherein the resilient element is operative to exert a compressive force on a pin mechanism of the lock in response to the operative engagement and thereby release the pin mechanism from a lock position, without requiring any pressure on the coaxial element on the other side.