Tank Seat Wheels: Tank seat wheel is compatible with a tank monorail. The ball bearing wheels are concave and do not fit racing shell tracks. Sold in sets of 6 wheels (the number to replace all the wheels in one undercarriage).
Dreher Seat Wheel Set: Compatible with Stämpfli/Janousek, Pocock, Hudson, Resolute, Empacher, Van Dusen, Fluidesign, BBG, Filippi, etc. We recommend changing all the wheels on a seat at the same time. Priced and sold as a set of 4 ball bearing wheels.