It´s aluminum made and was designed to fully comply with all the optical distances between camera-lens-port as if you had the subal housing: (all pics from Francesc Fontanals´ websites, a great spanish photog)


They also make a new port for the canon 60mm. I´s made of optical glass and fits the lens length without excess room:


Info:
+935406129
sagadive@hotmail.com