Restrictor with lockable pivoted catch

A restrictor device comprising a base 10 and a catch 11 pivotally mounted on the base and biased to engage an abutment 21. The catch comprises a slot 26 that has an exit. The catch is locked by a member 12 that, in a normal state, blocks the exit and, when manually moved to a release state, opens the exit. The slot 26 may define two arms. The locking member 12 may comprise a lever that is pivotally mounted at an end of one arm and biased to its normal state. This one arm of the device or the entire catch 11 may be laminated. The device is designed to restrict opening of a window to a certain amount. To release the restrictor, a two-handed operation is required, which is said to make it difficult for a young child to release the lockable member to the release state.