These 25/70-volt Lay-In Ceiling Speaker assemblies provide a quick and easy solution to speaker installations. The S-422A-2 and S-522A-2 are complete speaker assemblies including baffle and back box. This integral design meets or exceeds ASTM E84 Flame & Smoke Test with a 3-hour burn rating (UL 181), which allows this integrated package to be used in plenum type drop ceilings.