The Piston® Pro features some of the same great features as The Piston® Pro X minus a few bells and whistles. Features like all metal construction, OneTap™ hydro-pneumatic tire arms that make no contact on the bike frame, and tool-free wheel chock slides.But dont worry, this thing still sings.All metal constructionOneTap™ hydro-pneumatic tire armsNo frame contactPatented FastFit™ tool-free wheel chock systemPatented PedalPivot™Patented Flatlock™ hitch camNo Worries Limited Warranty2 – Bike capacity (Add-ons Available)67 lbs. per tray on 2” 2-b