2 6.5" - 6.75" CAR STEREO AUDIO SPEAKER SPACER MOUNTS 1/2" DEPTH RING ADAPTER - Walmart.com
Hawg Wired Black 6.5 in. Speaker Adapter Rings - 049964 Cruiser Motorcycle - Dennis Kirk
High Quality 3.5inch Car Rear Door Midrange Speaker Mounts Bracket Spacer Ring Adapter Plates For Bmw 3 5 Car Speakers Pad - Speaker Mounts - AliExpress
10 Inch Subwoofer Mounting Ring | Subwoofer Adapter | Garage Bagger Stereo