This is one of those items that wears out after many many flights. Probably not something to "stock up" on to prepare for crashes, but good to have after a year or more of flying the S1.
M
Mike C.
Mine went bad
Easy to fix...had a weird wobble after I replaced feathering shaft and this fixed it
F
Fer
Perfect replacement
Always at hand because when you have a crash these fall out and get lost