The U-profile guide rail is mounted only on one side of the aisle. The vehicle mounted steel roller "wheel" mounted front and rear on one side of the vehicle only.

The vehicle orientation within the aisle remains the same every time. Recommended in applications with nominal traffic. The advantage is the installation and cost of the single side rail and the use of floor level without rack beams on both sides of the aisle due to the low profile of the U-channel.