Drop hoops (also known as Stitch-around hoops) can be seed beaded, wire-lashed, filled with resin, and embellished to your heart's desire!
Crimp hoops have one unfinished end: add beads, then crimp to securely (permanently) close.
The loop end of the charm-holder style of wire hoops below is wire wrapped, and the other end is an openable hook that matches up to the wire wrapping. The sturdy heavy-gauge wire keeps its shape and stays closed, but is easy enough to open with a good squeeze when you want to add new charms and adornments. The hook end can be clipped to shorten, or widened with pliers to feed on hard-to-fit items such as beads.