This listing is for 5mm x 2.5mm sterling silver beads which fit on the chains that may be found here:
https://gotstonedjewelry.com/products/1-5mm-silver-ball-chain-chose-your-size
I got them with the intention of adding them between hearts and other shapes, as seen in the photo.
Photos are an example of how they may be used.
$5 each.