The RF41-20 is a 4-inch, full range, blind-mount, in-ceiling speaker which delivers true high-efficiency and performance across the operating bandwidth. The full-range drive design delivers maximum frequency response (71 HZ - 22 kHz, 10 dB) in a compact design. Mounting hardware is included and features fast and easy retrofit connections. For easy ordering, stocking, and installation, the RF41-20 includes a five-position tap switch for 25,70.7 and 100V applications with a transformer bypass position.