USP TWIST XL now features a patented locking system for increased ease of use and safety. Reduces the risk of needlestick injury. Transparent barrel allows easy inspection of solution when aspirating. Finger grips on the outer protective sheath prevent wet, gloved fingers from slipping when covering the needle for final disposal. XL needle includes larger bore (lumen) to help reduce back pressure during injections. Can be used with either sterile single use (white) or sterilizable handle (blue).