A large diameter extended length flat port for use with larger macro lenses and ikelite mirrorless or compact dslr housings a 67mm threaded front allows for the attachment of external macro lenses or diopters no separate adapter necessary recommended when using the canon 60mm macro with the ikelite housing for canon eos 100d rebel sl1 this port can also be combined with the mirrorless lens extension 22 inch to use the canon 100mm is usm lens