110 Volt Fuser Kit is designed to help maintain HP Color LaserJet CP4025n, CP4025dn, CP4525n, CP4525dn, CP4525xh, CM4540 MFP, CM4540f MFP and CM4540fskm MFP. The fusing assembly is the component that bonds toner to paper through a combination of heat and pressure so it needs to be maintained to maintain productivity in your HP printer.