Sea&Sea Spare O-Ring Set for MDX-5D Mark IV / MDX-7D Mark II Housings Item:O-Ring only The Diopter Correction Lens is

The Diopter Correction Lens is installed by dropping it inside of the viewfinder from housing side and tighten it by packaged tool (not removable underwater)

Optical glass / both side coating

Replacement / Spare O-Ring for Sea&Sea MDX-PRO Mark III and MDX-PRO D3 housings

which will turn on again after one second

Rubber Bush Base pasted on the housing (left) and Overlap structure with supplied Rubber Bush Base Sticker (right)

Sea&Sea Spare O-Ring Set for MDX-5D Mark IV / MDX-7D Mark II Housings Item:O-Ring only The Diopter Correction Lens isReplacement Spare O Ring for Sea&Sea MDX 80D, MDX D7000, MDX 70D, MDX 5D Mark III ver. 2, MDX 5D Mark IV and MDX 7D Mark II housings.