Abstract: A pressure equalising device (10) which has a squat shape and which has three positions which are a first unlocked and retracted position, a second locked and retracted position, and a third unlocked and extended position wherein the device comprises a spike (14) for piercing a container, a biasing member (12) to bias the device into the first position from the third position, an upper body (20) which supports the spike and which has a locking formation (28), and a lower body (40); wherein the device has a twist lock such that the device can be rotated to and from its first and second positions; wherein the twist lock comprises a slot (52) in the lower body which is positioned to receive the locking formation (28) to immobilise the upper body (20) in relation to the lower body (40); the invention provides an ergonomically acceptable and safe way to reduce the torque force required to open the typical jar to less that 2 Nm by equalising the pressures inside and outside the jar.