The Channel Tubing is the cap rail itself for a glass railing — the base every glass-topped run is built on. A U-channel groove runs the length of the tube to receive glass infill panels, so the glass seats into the rail for a clean, frameless look along a balcony, a stair, or a terrace edge. At 1.67" OD (42.4mm) with a.060" wall it is sized for glass loads, and solid 316 stainless adds marine-grade corrosion resistance indoors or out. Order it in a 16-foot length in 316 Polished or Satin. Every other part in the Glass Cap Rail line works off this base: splices join long runs, direction-change elbows carry the channel around corners and up landings, and end caps finish the terminations.