DesignRail Kit (TTS) Threaded Terminal Stair Post Kits by Feeney are tensioning termination posts.Used to begin a cable section and typically positioned at the top of the stairs. Use with QC Stair, and DesignRail Stair Rail Kits. Use TT side of CableRail Kits with Threaded Terminal Posts. Stair angle must be between 29 and 34 degrees. Visit DesignRail Kits Page for literature and installation. Available for 36" Railing only.