This clasp features a narrow opening that will snugly hold the fabric while allowing it to gather at the inside of the curve. The clasp will need to be mirrored for the opposite side so that the loops sit at the bottom. The loop is meant to be connected with thin chain.
The supports are necessary for the chain loop to print correctly. It should be printed upright with the loop at the bottom as to minimize the amount of support material used.
I find that using XTC-3D with brass powder mixed in leaves a beautiful finish on these.