All Honda's and many imports use a 1/8" BSPT (British Standard Pipe Thread) female port to install the factory oil pressure sending unit and these rather uncommon threads make it hard to add accessories without damaging the fine threads in the block. Recently added as an alternative to our aluminum version for those that needed a more compact and bulletproof option. Space is saved by not providing a body with enough real-estate to add a female port or two, so you cannot add the factory oil pressure sensor here, and it is stronger because it is not only shorter... its made from stainless steel. Getting oil to your turbo, aftermarket pressure gauge, and/ or accessory without damaging the OEM oil pressure port threads.
One end of the adapter has a OEM spec (thread size, length, and taper) male 1/8" BSPT thread and the other is -4 AN male. No more cramming 1/8" NPT adapters into the block, where they will ruin threads, leak, get over tightened and potentially split/ break the casting!
If you are installing the OEM pressure switch and need additional 1/8" accessories, I highly recommend looking at our Remote Fluid Log or the DIY version of it. If space is not an issue and you would like to keep the OEM pressure sender near its original location, take a look at the original BSPT Adapter and you can still send oil to something remotely. Weight, heat and vibration wreak havoc on parts... do them and yourself a favor by not having an oil fire! Its the smartest way to add multiple things that need oil, a pressure or temp source.