Here are the specs that Dave Merrill sent me about 6 months ago when I bought a bunch of drivers from him. FS- 55
QTS- .55
VAS- 11 L
Impedance- 5 ohms
SPL- 88
BTW- They work great in several bass reflex cabinets that I've built for them. Small mini towers @ 31 L with good bass to 40 HZ & stand mounted 16L cabinets with very good bass to 45 HZ. I have some of the stand mounted cabinets available if anyone is interested & can also build boxes for other DIY designs. Merrill cabinets are at the top of the attached linked page.