Estes Der Red Max 4" Plywood Fins and rings Upgrades

Estes Der Red Max Plywood Fins and rings Upgrades
For the 4 inch Max
3 - 1/8" thick Baltic birch plywood fins
Set of 3 - 29mm rings 
1/8" thick 
Note: These are a solid pc of plywood and are a bit heavier than the ones that come in the kits. 
Disclaimer. 
You use ollie-oop rocketry products at your own risk.