Mavin's 6.5" Woofer or Mid Range Driver, Replacement, Polk,JBL, Cerwin Vega and Boston Acoustics Verified So Far. 4 ohms, 150 Watts RMS Note; That depending on which Polk Driver you have, the mounting hole could be very slightly undersized, about 1/16" of an inch. What that means is that you would need to enlarge the hole by that 1/16 of an inch, a simple sanding drum on an electric drill does the trick and takes about 10 mintes for a pair of speakers. Also due the the massive weight of these woofers, we urge you to replace the standard wood screws with machine screws and tee nuts. This will keep your speakers from pulling loose due to the extra weight of the massive magnets. We have screw kits available for a small cost on the site. Mavin makes a very nice 6 1/2 inch woofer, 150 watts RMS and at 8 ohms, Design into your Car or Home Use. With a rubber surround, and stiff plastic coated paper cone, it is made to perform and last. This speaker was designed as a replacement for most 6.5" Woofers. Our Mavin A166-1SSM6 was designed to out perform any 6.5" driver, yet mirror closely the tonal qualtity of that staamdard style of speaker. It is a drop in replacement for most of the 6.5" Drivers. This driver has the foam / rubber gasket on the face of the speaker. Specifications 1.25" voice coil Power handling 150 watts RMS Rubber Surround Thick Plastic Coated Paper Cone 4 ohms Depth = 3.875" ( 3 7/8" ) (97 mm ) Frame Dia. = 6.7" ( 6 1/2" ) ( 170 mm ) Mounting Hole Opening Size 5.875" ( 5 7/8" ) ( 150 mm ) Weight = 5.5 pounds ( raw weight of the speaker, not packaged ) 48 oz. magnet structure 4 mounting screws, spaced 6.250" a part on the diagonal center to center ( 6 1/4" ) ( 159 mm ) The four mounting screw holes are 90 degrees to each other and spaced 4.435" a part on center. ( 4 15/32" ) ( 113 mm ) T/S Specs f(s) = 53Hz. Q(ms) =2.831 V(as) = 22.13 liters ( 0.781 cf. ) n(0) = 0.41% M(ms) = 13.37 grams R(e) = 3.87 ohms Q(es) = 0.767 SPL = 92 dB @ 1W/1m C(ms) = 0.67