A solenoid is a mechanical device made up of a wire coil, a case, and a moveable plunger. When an electrical current runs to the curl, a magnetic field arises around it, pulling the plunger inwards. Electrical energy is converted into mechanical work by a solenoid. The coil is many turns of tightly coiled copper wire. A significant magnetic field/flux is born when an electrical current travels through this wire. The curl is encased in a housing, usually made of iron or steel, which concentrates the magnetic field produced by the coil. The magnetic field concentration pulls the plunger to a halt, providing the mechanical force required to complete the task. Key Features: directly transfers electrical energy to linear mechanical motion serves as a relay to close the circuit by bringing a metal contact into place Product Specifications: SKU: SW125 UPC: 693006001685 Weight: 2.00 LBS Manufacturer Part Number (MPN): SW125 Alternate Products SKU: "18-6291", "89-26042" Quantity: 1 Heavy-duty. Fits: ARCO 70125; Ford gear reduction starters on late model 5.0L, 5.8L. Replaces: OMC 3854194; Volvo Penta 3854194-2