a paperboard carton and blanks therefor formed from a top unit and a bottom unit which are relatively slidable . a locking mechanism prevents the units from being fully separated . this locking mechanism comprises a locking flap hingedly coupled to and folded against a side wall on either of the top and bottom units and a corresponding stop member formed on an opposed side wall of the other of the top and bottom units . the stop member is comprised of two side glue flaps extending integrally from two adjacent side walls , each having a tab extending therefrom . the tabs engage the distal end of the folded locking flap to prevent full separation . advantageously , the locking flap is trapezoidal and the side glue flaps form a trapezoidal recess with the tabs forming the smaller base thereof . an air freshener material or insect poison can be located inside the carton .