A rectangular housing, containing for instance, electronic communication and measuring devices, is protected from shocks and is made stackable together with like housings by a dumbbell-shaped rubber member at each vertical edge thereof, thickened in each end to protect respective corners of the housing. Each rubber member has metal inserts for bearing upon the housing corners and is screwed or bolted and pinned to the housing. Opposite top and bottom ends of the bumper have cooperable keys and sockets arranged for positive stacking of the bumpers of different housings one atop another. Bumpers of increasing hardness are provided for housings of increasing weight. Tabs are also provided on the housings for direct inter-attachment thereof independently of the rubber members.