I recently bought 2 flip-snoots for use on my Inon z240 flashes. These snoots are actually 3D printed and are very well designed. I can choose 3 different ‘modes’ from a broad beam to a narrow beam and best of it all, I can change freely underwater! Even if I want to flip the snoot for a normal flash I just flip it. A minor disadvantage is that I can’t use a diffuser when it is flipped. Anyway , you will some snoot photos in the near future.
A review is available in Underwater Photography magazine issue 82.