These weld on fuel injectorbungs are designed for do-it-yourself fabricators whomake their own multi-port fuelinjection manifolds. Manufactured from 6061-T6 aluminium bungs. They can be used in two different ways. The manifold can be drilled to16mm (5/8") to suit an O-ring seal or simply remove the O-ring and weld them directly to the manifold. Onlyfits 14mm O-ring style injectors.