When select the early bird option on the kickstarter it doesn't give an option to add the 150m tether for $299. So backers could just add $299 on the early bird price. We will do rest of the work confirming what you get.
The wifi module couldn't float on the water, cause it's ip57 rating waterproof. It can withstand water, but not like being immersed of float on water for too long. So we con't suggest that put it in the water.
The lens is made of aluminum alloy and hard glass which are not that easy being scratched in normal use since we have done hundreds of tests.
And also the lens rest at the deepest point surrounded by metal plates, so in case of collision it's gonna scratch the metal instead of the lens.