The StrongArm™ technology of this premium tray mount protects your bikes and lets you load each one in 10 seconds or less. So you're guaranteed a speedy escape in your getaway car. Side-to-side position and rear strap adjustability lets you carry two bikes of any size, type, design, color, creed or flavor right out of the box, or carry up to 4 bikes with the optional Plus-Two add-on. The mast folds up and into itself when not in use, and it also folds down for rear-of-vehicle access.