POC ergo spine protector, very light use. This is the best and one of the most comfortable hard shell spine protectors you can get. Complete with detachable shoulder straps (shoulder straps not legal for USSA racing but are not required under a race suit anyway - I have never used them). This is a size small but these run large!. (Fits me perfectly at 5'8" where the Medium was too large). Would probably work for ~ 5'4" - 5'9"
Great deal at $60 shipped.