Yes it is compatible with all standard surfing leashes.
Anodised aluminium, with Stainless steel holding screws.
It creates just enough drag to keep your leash behind you when you paddle.
No, it is not heavy enough to sink your leash.
There are 2 stainless steel holding screws which join the 2 parts to your leash, it uses a fin key, super fast, super easy.
Just check that the screws are tight every few surfs. You can also put a small ball of board wax in the threaded end this will stop it loosing.
Do not over tighten as soon as you feel the screw biting that’s tight enough. See the installation video for more.