New in packaging BAL Heavy Duty Tire Locking Chock. Model # 28005. 2 in box. Scissors Type Locking Chock. Fit between tandem tires, it locks wheels by applying force to both tires. Aids in trailer stabilizing and prevents tire shifts. A hand-operated plated ratchet wrench (included) turns a drive nut, extending the chocks against the tires for locking and retracting the chucks for removal. Requires 2-1/2″ clearance between tires. Opens to 10″. Also a pack of Camco Leveler blocks.