The OEM Systems SC-800T 8" Full Range Ceiling Speaker is suitable for both commercial and residential use. Its dog-ear mounting system is compatible with standard sheetrock surfaces. The 40-watt speaker has a dual-cone tweeter and Kevlar driver that enhances the frequencies to give you a great listening experience. 

This has the commercial transformer for 70v/100v systems, but it can be removed and used as an 8 ohm speaker.

Transformer has 1-2-4-8-16 watt taps.