The "F" fittings are a convenient alternative to "Y" and "T" connectors. They are used to link two water-blocks in parallel using dissimilar tubing sizes. The F fittings are made of POM (Acetal Copolymer).

The advantage of these barb fittings compared to Y's or T's are:

• Cleaner routing of the tubing
• Reduction from "large" tubing size such as 1/2" or 3/8" to devices installed in space constrained areas and necessarily requiring 1/4" ports
• Minimal pressure drop