WARNING: When Series F bars are used in the vertical position, the spring end of the bar must be up to avoid bouncing out of the track. Shoring bars shall not be used in decking applications, unless otherwise specified. WARNING: Jack Bars, Saf-T-lok bars & Saf-T-lok II bars are not intended for use with cargo on wheels. Overtensioning of jack mechanism may cause damage to trailer sidewalls. NOTE: Cargo bars do not have load ratings due to varying conditions of trailer sidewalls.