Medical Disposable Blood Collection Needle Sheath https://www.klstopper.com/product/medical-rubber-products-series/disposable-blood-collection-needle-sheath.html Medical Disposable Blood Collection Needle Sheath Spec. Main size (mm) Length K20 20.7+0.3 K21-F 21.7土0.3 K22 21.9+0.3 K24-F 21.9+0.3