Drop ceiling speaker brackets for in-ceiling installation in commercial facilities with paneled ceilingsFor use with product ID 4103 (MST-660-2Y) and 4619 (MST-63-SK)This product is not compatible with product ID 6034 (MST-6F-A)Quality at a Fair Price: Monoprice's rugged design and rigid quality control standards deliver high quality products at fair prices.Service & Support : You're never on your own with Monoprice products! We have a full team of friendly and knowledgeable technicians available to answer your questions