An enclosure for small power supplies for cellular telephones, laptop computers and the like is formed in two layers. The first layer is an inner box constructed of a pair of about 0.8 mm thick PBT shells that enclose and retain the electronics. The second layer is an overmolding of about 1.0 mm. thick PVC that surrounds the shells, seals them together, and forms a strain relief for a cable attached to the electronics. The two-layer construction allows considerable savings in material and assembly costs.