Does your tractor lack power? Does your Backhoe bog down? Does the scoop strain to lift a bucket of rocks? These adjustment shims will help bump up the pressure and bring back the muscle to your machine. We recommend using a oil filled pressure gauge to aid in proper adjustment. We sell kits with the gauge and hydraulic connector included if desired. It is VERY important that you do not exceed your machines max PSI to avoid damaging your machine. We typically see about a 25% per increase over factory when these shims are applied correctly. You may need all 3 shims, or just one or two..it all depends on where your tractor is to begin with. Many new tractors are not adjusted properly by the dealer before delivery and can be below spec from day one. Also, the coil springs within hydraulic pumps naturally lose strength over time and this kit will allow adjustment to compensate for that. The sizes included in the kit are 0.1 , 0.2 and 0.4 ...Unlike some other pressure adjustment kits, we only use Genuine Kubota shims to insure 100% compatibility and performance. We recommend this modification be done by mechanically inclined persons and assume no liability whatsoever for the use of these shims. Detailed Instructions are included...the whole process takes just a few minutes and is very simple to understand if you choose to do it yourself!