This ring will center a BT-50 tube (24 mm engine mount tube) within a BT-80 tube. 1/8" Plywood

Two disks have a motor hook slot.

This ring is designed to fit a thick-wall motor mount tube and will not fit standard BT50 tubes. See BT-50 Thick wall motor tube

- 1.005", - 2.555",  1/8",  3.5