If your machine is not running up to its potential, this kit is for you. This Stage 1 kit includes a new air filter, pre-filter, oil filter, and spark plug. These simple to replace components can make a huge improvement in a machine that has been maintenance neglected. These filters are excellent quality replacements and Quad Logic approved. The spark plug is a genuine NGK plug matched for your Sportsman 400. Works on all 2001-05 Sportsman 400 models. This kit includes: - Air Filter - Water Resistant Pre-filter for the air filter. - Oil Filter - NGK Spark Plug (BKR5E)