A 23 gauge (0.6mm) hypodermic needle, 16mm (⅝ inch) long, on a standard Luer hub. Its wider bore draws up and transfers liquid far faster than a fine needle, which makes it the usual choice for jobs like adding bacteriostatic water to a vial to reconstitute it. It fits standard Luer syringes. The blue hub follows the ISO colour code for 23G. For single use. Supplied as a pack of 10.