The WWL-1 lens is made of glass and yes... it is very robust.
But this hard cap is a good investment, as you need to take good care of it every time it is out of the water!
A must have!
Fixed on the lens with 2 locks on each side.
Nauticam
2303 N Andrews Avenue
FL 33311 Ft. Lauderdale
United States. Florida
http://www.nauticam.com
Atlantis GmbH
Wolfener Str. 32-36
12681 Berlin
Deutschland
https://www.atlantis-onlineshop.de