RCB 22 track system including a 1350 mm long gate kit and a set of 4 x 2300 mm sections - complete with sail groove nuts and screws. 

RCB full-batten system - low friction main sail handling, retrofittable to Seldén E- and D-sections used during the 70's - 90's and many other brands.

The Seldén RCB (Round Circulating Ballbearings) full-batten system facilitates full-batten sail management, and makes it much easier to set and reef the mainsail.

The system is based on linear ball races and recirculating balls. The cars run with hardly any friction at all, even under the high compression loads produced by full-length battens. The track and cars are made from aluminium which, together with Torlon ball bearings, makes the system strong and durable. 

Installation manual: https://support.seldenmast.com/files/1380900717/595-670.pdf