ISO Standard Colour Codes Color-coded instant identification of catheter size 100% Medical Grade Silicone. Disposable Single Patient Use. Smooth tapered tip of catheter facilitates easy introducing to the urethra. The drainage eyes are accurately formed to permit affective drainage. The symmetrical balloon expands equally in all directions so as to perform its function of retaining bladder efficiently. Valve accepts Luer Lock or Luer Slip.