SurgiVet Needles with Peel-Off Sheaths. Promotes easy and accurate placement of catheters such as oesophagostomy tubes and central venous catheters. An alternate description would be that needles with peel-off sheaths allow for an easy conduit into the vessel for guiding and placement of the catheter. PTFE. Radiopaque needle and sheath. Sterile. Available in the following sizes: NPOS775 7G, NPOS875 8G, NPOS1055 10G, NPOS1570 15G, NPOS1770 17G. Each supplied with one needle and 5 sheaths.