Brand New Genuine Polk Audio RD5552-1 Mid/Woofer. RTiA1 & RTiA9 replacement driver.
Specs: 5.25″ (13.34 cm) (Round) Dynamic Balance driver with polymer composite cone and rubber surround – Mid/Woofer (4 ohm)
Use this speaker as a replacement for RD5537-2 used in the RTi4 AND RTi12.