JBL SSW-4 In-Wall Subwoofer. Required Amplifier: JBL Synthesis SDA-8300 (Connect up to eight SSW-4 Subwoofers with each SDA-8300 Amplifier). Width: 16.5” (419mm). Height: 25.375” (645mm). Mounting Cutout Size (H x W): 23-1/2" x 14-1/2".
eBay