This is a crystal chamber fin pack.
It is also available as single fin "part 04 single"
Single fins are easier to clean, sand and paint. The pack is more stable.
These fins are also available as laser-cutted version in my Shop
You can get all assembly parts here: Shop
For more informations and instruction manual klick here.
I recommend to use "Black Strong and Flexible" material.
"Strong and Flexible" garantees best performance and stability.
"Metalic Plastic" is more brittle. No guarantee for stability.
"Precious Metal" materials are soft and bend easy. No guarantee for stability.
"Stainless Steel" materials have bad accuracy (± 5% of any dimension). No guarantee for accuracy. This material is not recommended!