GoPro Mounting Tape Replacement -link
 

If you are like me, you go through a lot of mounts, and the replacements are not cheap. What we do is peel the old stickies off the bottom and replace with self-cut genuine 3M VHB (very high bond) tape. Like 30 times cheaper than buying replacements through GoPro (and more ecologically friendly)

You can get it a lot of places, here is one:

3M Products | 3M VHB Tape (90 mil Gray) | Adhesives, Abrasives