SnoWay's most current controller is the ProControl II. The ProControl II has a yellow casing on the brain box. The older ProControl I still has a yellow controller but the brain box casing is black. ProControl I components are not interchangeable with ProControl II components (you would need to replace the receiver "brain box" and the transmitter when switching from a ProControl I to a ProControl II) . The oldest controllers are the "Legacy Controllers" which are gray with a black brain box. If either component of your legacy gray controller is malfunctioning it is recommended to upgrade to the ProControl II system. When upgrading a legacy system you will need a solenoid wire harness kit along with a complete ProControl II control assembly (receiver and transmitter). Two harness kits are available, one for straight blades and one for v-plows. Legacy Wireless controllers are obsolete, Legacy wired controllers will eventually become obsolete.