PE 50 tubing is compatible with Hamilton 23s or 23 gauge needles. The difference between the 23s and 23 gauge needle is the inner diameter. The 23s gauge has a smaller inner diameter. The standard syringe that is used when connecting to PE tubing is the Hamilton Removable Needle (RN) termination. The syringe size is selected based on the injection volume of the application. For this application only custom needles are available. The custom needles are available in lengths from 0.375 – 12 inches, a 2 inch length is recommended. Also these needles are available in point styles 2, 3 and 4, point style 3 or blunt is recommended for this application. These needles are sold in convenient six-packs. The needle will connect directly to the syringe and the PE 50 tubing will fit snugly over the 23s or 23 gauge, blunt needle.