Quickie style replacement sling seat. Slotted 6 hole pattern: 1", 1", 3 1/4", 3 1/4", 3 1/4", 3 1/4". Six sizes available: 15"wide x 16"deep, 16"wide x 16"deep, 17"wide x 16"deep, 18"wide x 16"deep, 19"wide x 16"deep, and 20"wide x 16"deep. Rails are not included. Sold as each.