This Demco Model DA16 Surge Brake Actuator for disc brakes has a 16,000lb towing capacity with 1600 lb of tongue load, and secures to your trucks 2 5/16 inch towing ball. This model includes the electric lockout solenoid, designed and required for use with hydraulic surge disc brakes on your boat trailer. This model is ideal for tandem and triple axle boat trailers. Demco brand actuators feature the highest quality steel construction with zinc plated coated components and exterior for excellent corrosion resistance for both freshwater and saltwater towing applications. Additionally, Demco Actuators integrate the common Level Lock latch design with their easy trigger latch system. You will literally be hooked on this easy trigger Latch system by Demco the first time you use it. Securing your coupler to your towing ball is all easy as lowering it, and removing it is just as simple, with the lift of the latch and raising the jack. Specs: -Mounts to a 3" Wide Trailer Tongue using (2) 1/2 x 4 1/2 Boat Trailer Bolts -Use 2 5/16" Trailer Ball -G.V.W.R of 16,000 lbs (Gross Vehicle Weight Rating) -1600lb Tongue Load -Has two Mounting Holes 3" On Center Features: -Hydraulic Surge Actuator for Operating Disc Brakes -Includes Electric Lockout Solenoid with Heavy Duty Protective Shield -Zinc Plated and rated to 500 Hours in a salt spray test -Composite Master Cylinder made from glass reinforced nylon, which means no more Master Cylinders rusting on the inside from moisture or brake fluid -Includes heavy duty breakaway latch system -Made in the USA