The 31155 Focus Gear for Canon EF 100mm f/2.8L Macro IS USM Lens from Sea & Sea fits this Canon lens only. It can be used on this lens in the MDX-5D Mark III, MDX-7D, MDX-PRO 5D Mark II, MDX-PRO Mark III, and MDX-40D housings from Sea & Sea. This lens is compatible with the 30105 DX Macro Port Base and 30110 DX Macro Port 50 II. Focus is adjustable via the focus knob on the housing.