The buckle part of this product allows you to adjust the belt length. Remove the 3 screws and cut the belt to the length you desired, then put back the screws, done.
Not too long, not too short, you can make the strap skin-fit to the size of the item (e.g. li-po battery) you want to fix.

Set includes:
Strap x2pc
Backup buckle x1set