"The QED Envirograf R-AFH2 is an acoustic and fire prevention hood for in-ceiling speakers. It is essential to fit covers to all speakers fitted in fire rated ceilings & walls. Not only for airborne and impact sound, but to stop fire penetrating into the ceiling & wall to meet UK building regulations, keeping the fire rating of the ceiling or wall. Without this cover, a 1 hour rated ceiling would collapse in 15 minutes. These must be fitted in all ceilings as well as ceiling to loft area to give full fire protection. The cover can be easily fitted from below, and is supplied with pins to fix the cover to the plasterboard."