AC Performance straight metric male to 3/8 hose barb fitting adapter (M12x1.5)
Product description
The essentials: what this adapter is for
If you’re trying to connect a hose to a metric fuel/oil setup, this AC Performance straight adapter is aimed at that exact job: it’s a male metric thread (M12x1.5) to a hose barb adapter. In plain terms, it helps you bridge between a threaded port and a barb-style hose connection, using a straight-through design.
On paper, the appeal is pretty straightforward: lightweight CNC-machined 6061-T6 billet aluminium with a black anodised finish, plus a natural aluminium spacer / washer included for the interface. It’s the kind of fitting people choose when they want something neat and solid without going down the route of generic reducers that may not match well.
Key takeaways: what stands out
The biggest practical win here is the thread-to-barb conversion. That means you’re not just swapping a connector for another barb—you’re matching a specific metric thread size to a hose barb diameter.

A couple of details are worth noting because they matter when you’re fitting it in the real world:
- Straight adapter style: helps keep routing simple, especially where you don’t have much space to play with.
- Black anodised finish: a durability-focused touch, particularly relevant for fuel/oil environments.
- 6061-T6 billet aluminium, CNC machined: tends to be more consistent than press-formed hardware, and it keeps the weight down.
- Includes an aluminium spacer/washer: this can reduce the “it just doesn’t sit right” hassle you sometimes get with mismatched adapters.
Still, no fitting is perfect for every build. If your installation needs a different thread pitch or a different barb size, this one won’t magically compensate.
What you’ll notice day to day


Once installed, the day-to-day difference is mostly about fitment and confidence. A proper thread engagement and a properly sized barb connection usually means fewer weeps and less fiddling during hose changes.

For a micro example: imagine you’re working on a fuel or oil pump inlet and you’ve got a port that’s M12x1.5, but your hose is designed to clamp over a barb. Instead of cobbling together a temporary connector, this adapter gives you a direct conversion path—use the barb end for the hose, and the threaded end for the pump inlet.
The essentials: technical details (so you don’t have to guess)
Tech specs
- Name: AC Performance Straight Metric Male M12x1.5 to 3/8 Hose Barb Fuel Oil Pump Inlet Fitting Adapter
- Type: male metric thread to hose barb adapter
- Material: CNC machined 6061-T6 billet aluminium
- Finish: black anodised
- Thread: M12x1.5 (male metric)
- Barb size: 3/8" diameter barb
- Adaptor includes: natural aluminium spacer / washer
- Design: straight adapter style with aluminium ring spacer/washer
Who it suits (and who should be cautious)

This is a sensible pick if you’re working on a fuel or oil pump inlet and you’ve already identified that you need M12x1.5 male metric thread to a 3/8" hose barb connection. It’s also a decent “keep it tidy” option for builds where you’d rather have a CNC-machined fitting with a proper finish rather than a rough adapter.
It may not suit you if: - your port isn’t actually M12x1.5 (wrong thread size/pitch is the classic deal-breaker), - you don’t have room for a straight fitting in your layout, - you were hoping for a universal adapter to cover multiple hose sizes.
Also, take a careful look at how you’ll seal it. The product includes an aluminium spacer/washer, but whether you need extra sealing (for your specific setup) depends on what your mating surfaces and port design already provide.


Practical buying checks before you order
Before you commit, double-check: - Your mating thread really is M12x1.5 (not just “M12”). - Your hose is intended for a 3/8" barb connection. - You’ve got the space for a straight adapter and that the fitting won’t interfere with nearby components. - The washer/spacer included matches how the port is designed to accept it.

If you’re comparing alternatives, this kind of adapter usually sits in the “properly machined, build-specific” category—more targeted than generic plumbing-style connectors, and often the better choice when accuracy matters.
In the box
- The adapter fitting
- Natural aluminium spacer / washer
Is it worth it?
This AC Performance straight metric male to 3/8 hose barb adapter is worth considering if your project genuinely needs M12x1.5 to 3/8" barb and you want a black anodised, CNC-machined aluminium solution with a spacer/washer included.

You may want to skip it if your setup doesn’t match those sizes exactly, or if you need a different angle/style or a different barb diameter. In that case, you’ll save yourself time by choosing an adapter that matches your thread pitch and hose barb size from the start.
Mini FAQ


Will this fit an M12x1.5 port?
It’s built specifically around a male metric M12x1.5 thread, so if your port matches that, it should be the right direction.
Is the other end designed for a 3/8" hose barb?

Yes, the barb end is specified as 3/8" diameter, so the hose should be compatible with that clamp-on barb approach.
What material is it made from?
It’s made from CNC-machined 6061-T6 billet aluminium with a black anodised finish.
Does it come with a washer?
Yes, it includes a natural aluminium spacer/washer as part of the adaptor package.
Is the straight design limiting?
It can be, depending on your space constraints. A straight adapter is great when routing is simple, but if you need clearance or a particular angle, a straight fitting may not be ideal.
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