Improved locking mechanism

A locking support assembly for a slide-out side of a vehicle or trailer comprising: a support arm assembly adapted to support the slide-out side comprising: i) a first support member (10) having a first end and a second end, the first support member being connected to the vehicle or trailer such that the first end is located proximal to the side of the vehicle with the slide-out side and the second end is located remote from the side of the vehicle with the slide-out side; ii) a second support member (11) having a first end and a second end, the second support member being connected to the slide-out side such that the first end is located proximal to the side of the vehicle with the slide-out side and the second end is located remote from the side of the vehicle with the slide-out side when the slide-out side is in a stowed position; the second support member (11) being movable with respect to the first support member (10) to support the slide-out side when the slide-out side is being moved from the stowed position to an unstowed position and from the unstowed position to the stowed position; wherein the second end of the first support member (10) is provided with a locking assembly (19) and the second end of the second support member is provided with a locking pin (18), the locking pin (18) being adapted to engage with the locking assembly (19) when the slide-out side is in the stowed position.