I only opened the package and attached the rubber band for confirmation. The following is a product description: Size: Fixed side adapter: 40mm x 60mm x 21mm Size: Washer side adapter: 40mm x 56mm x 34mm Weight: 78g (when large O-ring is attached) Material: [Body] Glass fiber reinforced plastic / [O-ring] EPDM Included: Adapter body (fixed side, washer side) x 1 each / O-rings (large: inner diameter approx. Φ56mm, small: inner diameter approx. Φ42mm) x 1 each / Silicone bands x 2 (1 spare) Thank you.