This pack includes: 1x Hall effect RPM sensor, set of screws, 2x Neodymium fan magnets and mounting brackets for .50 and .90 size nitro engines. The magnets are 4mm diameter x 2mm thickness. 

Suitable for all governors and flybarless systems, excluding CSM and Futaba. It comes with its standard servo type plug, an adapter is required for some flybarless systems that use JST connectors.