This PTFE-Lined Needle features 304 Stainless Steel tubing on the outside with a Luer-lock Hub. The inside of the needle is lined and the tip is made of PTFE (Teflon).
This product is available in (3) sizes: 18g, 21g, and 25g. Note the p/n is 100-10-18-xx where xx is the gauge (18, 21, or 25).
18g has 0.064" [1.62mm] Outside Diameter (OD) and 0.042" [1.07mm] Inside Diameter (ID).
21g has 0.064" [1.62mm] Outside Diameter (OD) and 0.032" [0.81mm] Inside Diameter (ID).
25g has 0.050" [1.27mm] Outside Diameter (OD) and 0.020" [0.51mm] Inside Diameter (ID).