Its a fact of life. Ratchet backband straps can break.
This kit is a pair of replacement plastic ratchet tabs, the webbing that is attached to them and the metal buckle for attachment.
Pyranha back band straps are designed to handle a serious amount of force, using a climbing grade, bartack stitched webbing construction, and featuring a highly corrosion resistant, anodized speed buckle such as those commonly found in climbing harnesses.