Canon OEM Tripod Mount Ring C(W II) for 70-300mm f/4-5.6 L
Canon OEM Tripod Mount Ring C(W II) for 70-300mm f/4-5.6 L,Amazon.com : Tripod Mount Ring, iShoot 78mm Lens Collar,Amazon.com : Canon Tripod Mount Ring C (WII) for EF 70-300,Amazon.com : FocusFoto Metal Tripod Collar Mount Ring 1/4,Amazon.com : DSLRKIT Tripod Collar Mount Ring C (WII) for