Fig. 2.

Illustrates the post-IV catheter insertion. Part number 1 is a plastic catheter positioned within the vein. The catheter needle sheath (part no. 2) is completely fixed. The narrow head of the safe chamber syringe (part no. 4) is separated from the needle sheath by twisting. The used needle (part no. 5), which is connected to the cylinder of the safe chamber (part no. 6), is trapped by the piston of the safe chamber (part no. 7) in the body of the safe chamber (part no. 4). Considering the metal needle is shorter than the safety chamber, its sharp head is completely locked inside, like a syringe.