STL parts and 3DM source file (saved as 5th version of the Rhino3d model for better compatibility and for your comfort) of classic bracelet/chain link in 4 different sizes.
Sizes (width of chain): 4, 6, 8 and 10mm. Basic dimensions are shown on preview pictures.
For each chain size provided 2 types of the clasp. Both are pretty simple for production. The simpliest version is easy lock. Another one is classic lobster clasp but without embedded spring (the same as used in classic Gucci's bracelet that served as reference for this project).
Single link volume (and estimated weight for sterling silver):
Detailed information about volume and dimensions is shown on screenshots with STL diagnostic data.