The Cardiff valve is used to overcome the problem of backtracking when two solutions of different densities are used. The higher density solution should always be attached to the lateral port.
Lipid-Resistant Three-Way Stopcock
Lipid-resistant three-way stopcock with one male Luer-lock port and two female Luer-lock ports.
SOL-M Blunt Fill Needle
18G x 40mm (1.5 inch) blunt fill drawing up safety needle