Specially designed for Honda XR400s as a trail tool. The socket is designed to fit into the plug cavity and allow the user to choose between the Motion Pro spark plug ratchet wrench, a 3/8' ratchet or 13/16' wrench as well as a tool kit bar or phillips screwdriver through a 8.5mm hole for removal and installation. Will work on other XR's and bikes with 18mm spark plugs. Other applications: Honda: XR500R 83-84, XR600R 92-98, XR650L 93-00. KTM: 400SXC 2000, 620LC4 96-97, 620SX 97-98, 640 LCA 99 Yamaha: XT225 92-99, TT600 85.