1 handed activation, w/fingers behind exposed sharp, automatically retracts needle . Pre-removal capability & works w/all luer lock & luer slip syringes. 50/Bx 8Bx/Cs #85081-18x1 #85091-18x1.5 #85061-20x1 #85071-20x1.5 #85041-21x1 #85051-21x1.5 #85021-22x1 #85031-22x1.5 #85231-23gx1 #85291-25gx5/8 #85211-25gx1 #85011-25gx1.5 Latex Free UNSPSC#42142523