GoPro Handheld Mount - Scuba Diving

I saw a similar item for sale online and thought why not just print my own! Intended for scuba diving but is probably applicable elsewhere.
Printed in bright orange PLA so if the worst should happen I might find it!
Printed at 100% infill to ensure the chamber in the middle is airtight so if you do let go it should float to the surface. There's also a loop for a wrist strap (I stole one from my old Wii nunchuck).

UPDATE: Turns out it wasn't airtight at all, down at about 7 metres or so fo