NextGen glides optimize your HOSS 700 for use with truckmount and portable extractors. This kit includes two types of glides. The NextGen 1 glides (prev. #121831 or 51-072) provide smooth operation and thorough extraction on all carpet types and are designed to maximize truckmount extraction capabilities. The NextGen 2 glides (prev. #117833 or 68-226) deliver outstanding performance with portable extractors. Glides can be changed out in just minutes with a screwdriver.