Since 1925, Keilwerth has concerned itself with creating saxophones that allow the musician to shape his own sound and style. With this in mind, Keilwerth took the technical advantages and improvements of the SX 90, and added some extra features to truly make the musicians instrument his own. The result was the SX 90 R (the R standing for tone hole rings), a saxophone reminiscent of the old Conn and Buescher saxophones of the 1940s. There are no reviews yet.