This Ocean Kayak backband provides solid lumbar support. Made of yellow, injection-molded EVA foam with webbing strap, 2 super locks and 4 brass snaps. This will fasten onto most sit-on-top kayaks. See Back Band Photo, Rear Veiw.
With some effort this could be converted to the classic 1.5 inch side release buckle style attachment, but it may be more practical to simply install pad eyes. See the related article below.
The Ocean Kayak Comfort Backrest is 21.75 x 11.25 inches. Part Number 07.1014.0000.
Related Article: Backrests, Kneestraps and Paddle Leashes for tips, selection and use of the right gear.