Collar, harness or leash mounted electroluminescent strips are powered by an electronic inverter circuit and batteries inside a plastic housing. A lid on the housing is thinned around a central push button. An extension of the push button activates or deactivates a push switch in the base. An O-ring in a peripheral groove on the base seals a complementary peripheral projection of a lid. Cylinders extend from sides of the base. Knurled and threaded inserts are held in the cylinders. Complementary lid lugs hold set screws which are screwed into the inserts, tightly compressing the O-ring. Knurls on the base and a keeper opposite the knurls hold the housing on the collar. An opening for the electroluminescent strips is partially surrounded by the lugs.