JK Jack BaseAEV's Jack Base provides 3 1 2 inches of additional lift height to the stock Wrangler's "scissor" jack allowing tires of up to 37" or more to be changed with ease and stability. Many people don't realize that the stock jack won't work to change larger tires until it's too late, leaving them stranded on the side of the road or worse, on the trail. The large 7. 5" x 10. 5" base gives the jack better stability in off road and soft soil conditions. Handy