BD Vacutainer? Safety-Lok? blood collection set The BD Vacutainer? Safety-Lok? blood collection set is simple, easy to use and safety engineered. The safety mechanism can be activated immediately after the blood draw and helps protect against needlestick injury. It is also offered with a preattached holder to add convenience and help ensure OSHA single-use holder compliance. With luer adapter 21G x 3./4 inch needle 12 inch tubing 50 per box