Fittings and adapters for custom liquid cooling loops: compression fittings for soft and hard tubing, rotary and angled connectors, extenders, plugs and thread adapters. They suit PC builders who are assembling, expanding or reworking a water-cooled system. Our range has over 350 products, with leading names including EK Water Blocks, Thermal Grizzly, Bitspower and Barrow.
How to choose fittings and adapters for a liquid cooling loop
Thread and tube size. Most PC water cooling blocks, radiators and pumps use a G1/4 thread, so G1/4 fittings are the usual starting point. The fitting must also match your tubing: soft tubing is specified by inner and outer diameter (for example 10/13 mm), while hard tubing is specified by outer diameter only (for example 12 mm or 14 mm).
Soft or hard tubing fittings. Compression fittings for soft tubing grip the hose with a collar and are forgiving if you need to reroute. Hard tube fittings use an O-ring seal and a compression ring, and they give cleaner, straighter runs but need precise cutting and bending. Check the product title, as a fitting made for one tube type will not seal properly on the other.
Shape and angle. Straight fittings are the simplest, while 90-degree and 45-degree rotary fittings help where a tube would otherwise kink near a graphics card or the case panel. Extenders, multi-way adapters and T-pieces add flexibility when you plan the layout, so count how many connections each component needs before you order.
Material and finish. Fittings are commonly made from nickel-plated or coated brass or copper, or from acrylic and other plastics. Try to keep the metals in the loop consistent to reduce the risk of galvanic corrosion, and choose a finish that matches your blocks and radiators if appearance matters to you.
Valves and quick disconnects. Drain valves and quick-disconnect couplings make draining and maintenance far easier, especially when you want to remove a graphics card without emptying the whole loop. They cost extra space and add flow restriction, so fit them where servicing is most likely.
Brands of fittings and adapters we carry
- EK Water Blocks: a Slovenian manufacturer known for complete custom loop ranges, so its fittings sit naturally alongside its blocks, reservoirs and pumps.
- Thermal Grizzly: a German brand best known for thermal paste and cooling accessories, now also offering liquid cooling parts.
- Bitspower: a Taiwanese specialist with a long record in machined fittings, with many finishes and angled, rotary and extender designs.
- Barrow: a Chinese manufacturer producing a large number of fitting styles, frequently chosen for builds that need many connections.
- Alphacool: a German brand that makes both closed-loop and custom cooling components, with fittings designed to match its radiators and blocks.
- Koolance: known for quick-disconnect couplings and ready-to-use cooling hardware.
- XSPC: a British brand with a history of custom loop kits and the fittings that go with them.
Also in our range: Optimus, Corsair, Watercool, Phanteks and Lamptron.
Frequently asked questions about liquid cooling fittings
What thread size do PC water cooling fittings use?
Most PC water cooling fittings use a G1/4 thread. This is the standard on the majority of CPU blocks, GPU blocks, radiators, reservoirs and pumps. Always check the port specification of your components before buying, because a few products use a different thread.
Can I use the same fitting for soft and hard tubing?
Usually not. Soft tubing fittings clamp over a hose, while hard tubing fittings seal around a rigid tube with an O-ring and compression ring. Some fittings are sold as suitable for both, but only if the product description says so.
Can I mix fittings from different brands in one loop?
Yes, in most cases, because G1/4 is a common standard and fittings from different manufacturers generally thread into the same ports. Make sure the tube diameter matches and try to avoid mixing different metals, as that can lead to corrosion over time.
Do I need a drain valve or quick-disconnect fitting?
A drain valve is not essential, but it makes emptying and refilling the loop much simpler. Quick-disconnect couplings are most useful if you plan to remove components regularly, as they let you separate a part without draining the whole system.
