This spacer kit will reduce any Wheeldock unit by 2-3/8 inches in 1/8 inch increments and consists of 6 spacers with the following thicknesses: 1/8, 1/4, and 4- 1/2, inch spacers. With this kit you can reconfigure a model 5 down to a model 1 or any size in between. Comes with 2 reusable zip-ties.