No more boxes! That is the cry of our customers. The Stay-IN-Play DUO answers the cry. Duo's small operating unit is installed under the hood so you never know it is there. No messy components scattered in the towed vehicle to complicate things; just a small operating module to control the towed vehicle brakes with no physical connection to the motorhome.

DUO combines the power of air pressure and the gentleness of vacuum to give you the fastest most powerful self contained supplemental brake ever. Duo uses the power and speed of air pressure to activate your towed vehicle brake pedal while creating vacuum for the power brake system. These two features combine to create the only progressive and proportionate vacuum assisted system with total control. Duo requires BOTH deceleration AND coach brake lights to apply the towed vehicle brakes. By combining two separate signals the need for complicated electronics is eliminated, which provides you a more reliable long lasting system. In addition, DUO is the pioneer in user friendly operation; "Just Turn it on...and Tow." This simple technology was first introduced in 2003. Tried and true, DUO does not have to be taken in and out for normal operation of the towed vehicle. Unhook the car and drive off, thats all. No box, no wires, in fact, no physical connection to the motorhome at all.

The Stay-IN-Play DUO system energizes the towed vehicle’s power brakes without the engine running, so you have a soft brake pedal. Once engaged, DUO replenishes the vacuum in the car's power brake system. By replenishing vacuum, gentle smooth pressure is applied to the towed vehicle’s brakes. With the power brakes active, only 10 - 12 pounds of pressure is required to provide a gentle smooth stop.

Activation of the towed vehicle's brakes require BOTH deceleration and the brake lights from the motorhome. Once BOTH signals are present, DUO gently applies the brakes. There is no complicated gain or sensitivity to achieve the proportionate balance of brake effort, it is all automatic. Automatically, once engaged, DUO will apply progressive brake effort in the towed vehicle. Because DUO uses both brake lights from the coach and deceleration, there is absolutely no delay. This becomes critical in a panic stop. Systems that use only deceleration must "think" first, is this a step grade, is this a large bump, or is this stopping? Time translates to feet while towing and in a panic stop, inches are important. No self contained system applies brakes faster than the DUO.

"Coach Notification" is another important aspect of any supplemental brake system. Some claim to have it, but really do not; while others do not really tell you about the position of the brake pedal in the towed vehicle. Without question, the most important information while towing is the status of the braking system in the towed vehicle. "Are the brakes applied?" That is the question. When researching brake systems, ask the question, "Do you have coach notification FROM THE TOWED VEHICLES BRAKE PEDAL SWITCH?" Many will claim to have a signal but do not, and others will have a signal from some other source. The only reliable and complete signal must originate from the towed-vehicle's brake switch. If the light is on, the brakes are on, period. What you do not want is a problem while you are towing. Knowing the position of the brake pedal gives you that peace of mind.

Simple on/off towing, the gentleness of vacuum, the speed and power of air pressure, dual signal activation, and reliable coach notification all combine to provide the most powerful easy to use system available today.

Installation instructions

Old part number

SMI_0807

SMI_99251

"...acts more like real brakes, it's the best!" - Jim Clarkson, Hitchsource First Customer For SMI Duo