Rattle reel for ice fishing.
2 16mm X 5mm bearings with a 5mm ID
4 M4x12 SHCS
1 small bell or ball bearing for the rattle
I used a piece of flat stock steel and bolted the spool to that using a nylon washer, wing nut and bolt. How you mount this to your fish house will be up to you.
The tension isn't something that can be adjusted on the fly unless you have a set of hex key wrenches with you. Maybe in an updated version i'll add that feature.