Flat port mounts and extension rings are made from technical synthetics. In different lengths and adapted to the respective lens, they are all fitted with a flat parallel glass. The diameter of all flat ports is 105mm – the total length always given including the thread except for extensions. The optical coating on the inside is available as option.

see:

SEACAM P60 MACRO PORT

SEACAM P105 MACRO PORT

SEACAM P120 MACRO PORT