This watertight door improves the quality of videos under water and avoids the blur that one can have with the original box. But beware !!! These doors fit only on 60 meters waterproof case SPK AS1 (the one sold with the AS15 camera model) it does not mount on the 5m waterproof case SPK AS2 (the one sold with the AS30 model) People (like me) who have a camera 30 AS and who wishes to have net videos under water must purchase the housing SPK AS1 and doors AKA RD1 all at about 75 at amazon