One 4.0inch polypropylene woofer and one 1.0inch convex aluminum tweeter with FerroFluid cooling. Rapid installation blind-mount, fixed- wing mounting mechanism with constant tension design affixing to ceiling thicknesses ranging from 0.025inch (0.6mm) to 1.87inch (47.5mm). Easy access five-position selectable tap switch for 25-, 70.7- and 100volt applications with transformer bypass position. Separate tool-free magnetic grille and bezel assembly for ease of install and in-field painting. Powder-coated steel grille for lasting durability. 90dB average sensitivity offers high-output capabilities and reduced amplification costs.