An aluminium barb adapter with a 1/16-27 NPT thread, the smallest common tapered thread in the range. The barb accepts a push-on rubber or silicone hose secured with a small clamp, which is exactly what is needed for low-pressure signal and vent lines: boost reference to a gauge or wastegate, vacuum feeds, and small breather runs. It is a far tidier and more reliable solution than forcing hose over a bare thread and hoping the clamp holds. Aluminium keeps the weight down and suits alloy components where a steel fitting would risk galvanic corrosion. Use a suitable thread sealant on the tapered thread, and do not overtighten it into a soft alloy casting.