14cm long plastic & diamante straps, with 10mm hooks either end, hook these to your bra and the other end to a 10mm loop on a sewn on or hook on strap. This way they can be removed when the bra is laundered.

Ready made straps which are used when making part fabric straps to give some adjustment, with the correct sized finding, designed to be sewn on/permanently attached to the bra/lingerie.
With a ring at one end (which you would add a fabric strap to or other extention) and slider for adjustment along the strap. Unusually, these have a piece of rouleau strap at the other end to sew directly to the bra, so are a little more interesting

sold per pair