Vortez published a review on the SteelSeries PRIME and PRIME+
A quote from the article:
Two key attributes have been earmarked to set the designs apart from the mainstream. The first is "Prestige OM", a brand new switch design which utilises an optical-mechanical approach. The second is the latest TrueMove optical sensors developed in partnership with PixArt, capable of 18000 CPI and one-to-one tracking at velocities up to 450 inches per second.SteelSeries PRIME and PRIME+ Review