Simpson Vortex II UTV and Off-Road SeatsSimpson Vortex UTV and Off Road Seats Simpson Vortex UTV and off road seats provide high containment. Because of their cutaway lower bolster design, these seats still provide easy entry and exits. They have traditional tube style frames mated to laser cut seat bases, which utilize a variety of different modular mounting rails. When used with the required vehicle specific mounts, they will attach to your factory sliders without raising the seat height.