Model Aviation Products Fuel Line Clips
MAP 4mm Tidy Clips - Using CA, glue in to position any 4mm line in your installation.  Molded from durable nylon with a large base ensure a superior glue joint.  (Pkg of 10)
 
MAP 6mm Tidy Clips for 6mm or 1/4" Tygon tubing.  Large base for superior glue joint.  (Pkg of 8)