Duplo Brick 1 x 2 x 2 with Side Cutouts and Channel in Top

Reference

42234

Duplo Brick 1 x 2 x 2 with Side Cutouts and Channel in Top (part 42234) is a LEGO element. CollectORbuild's catalog records it in 37 sets, including Airport Action and Ambulance & Driver. It has been produced in 7 different colors.