Micnova MQ-TMR04 Tripod Mount Ring for The Canon EF 100mm f/2.8 USM, EF 180mm f/3.5L & EF 65mm f/2.8 Lenses (Black) Professional Grade Improves Tripod-Mounted Lens Balance Simple to Install and to Remove Rotates for Horizontal/Vertical Shooting Thumbscrew Tightens and Loosens Ring