UT is slightly wrong. The Nitron Race unit is adjustable for preload, rebound, and high and low speed compression.
I went for it as the company was in Oxford, I liked the products, and I got a discount as they had my bike for a week to build the shock to suit as they hadn't done one for a Tenere before.
Thusly whenever anyone buys a shock from them, they get a little picture of my bike with it!

I think there is a Wilbers option as well, but again it isn't that cheap.