These were $106 (Without shipping) for a set.
They are made by some company under license from Paioli.
They are meant for an Enfield Bullet and some Triumph 500cc bike etc.
They are 315mm long (eye-to-eye), mounting hole diameter is 10mm, the mounting surfaces are 18mm wide, the springs are 54.5mm wide and the thickest part is 63.5mm. The springs have a thickness of 7.3mm (If you might wonder :P) and the spring has 5 settings (The damper has unlimited settings, as it's gas ;))
They are sold at <www.kickstarter-classics.de> through an E-bay shop