Purchased in 2020 but never used, so it's in new condition and has been stored at home. Product weight: 18 g Exclusively for MT-800N Seat post clamp One-touch type, compatible with posts with a diameter of 27-35mm Convenient when the stays included with the carrier are short or when the bicycle doesn't have screws for attaching stays. Suitable for attaching to the seat post instead when the bicycle doesn't have eyelets for carrier mounting.