The ESCO 12500 Heavy Duty Stackable Cribbing Stand Kit make lifting easier and faster. Stands be used individually or stacked together for various heights. Stands have a recessed 7 in. x 7 in. area made to securely support hydraulic cylinders, outriggers, etc. Kit contains 3 cribbing stands; 3in, 6 in. and 9 in. and diameter for each stand is 12 inches.