The comfort seat (pictured) is designed with a flatter, wider cushion, as well as additional padding to enhance the rider's comfort on any model year R1100RT or R1150RT (Note: R1150RTs after a certain production date came standard with this seat, please compare the picture to your seat before ordering).
The low seat offers a more narrow cut at the "waist" of the seat to allow the rider to get closer to the ground without sacrificing padding and comfort.
Dimensional weight listed.
BMW R1150RT|R1100RT Comfort or Low Seat
BMW Original Parts