A label printer comprising a cassette-receiving bay, said cassette-receiving bay having a base, a top opening opposite the base, and a locking mechanism extending from said base, said locking mechanism having a locking part, said locking part being movable in a first direction and biased in a second direction opposite to said first direction, said locking part having one or more projections such that a force thereon directed towards said base causes the locking part to move in the first direction and wherein said locking part is biased to move in said second direction when the force is removed.