Frigoboat, Speed Control Board for Danfoss/Secop BD35F/BD50F Compressors, with 12/24 Volt Switch
 
This is a secondary circuit board that mounts with female connectors to the Danfoss/Secop 101N0200 and 101N0210 Controllers
Compressor speed is adjustable from 2,000 RPM to 3,500 RPM with small screwdriver
Comes with a 12/24 Volt selector switch
This is for the speed board only - Danfoss/Secop controller not included