I purchased a pack that came without fins and after some searching I only found resin options. So instead I decided to make some by hand out of 1/8" thick by 1/2" wide aluminum. All you need is a vise, cutting wheel, and a metal file. Im thinking of using hot glue to set the fins into the rocket and with this the depth of the fin can easily be set. I suppose one could also easily drill a hole into each and attempt to make them moveable as well- I'm thinking with a small piece of spring rod through the hole and pushed into the slot. Anyhow please let me know what you think.