When your design application requires fractional tubing, you'll need Swagelok's SS-400-3 tee which has a 1/4-inch outer diameter. Its stainless steel construction takes the worry out of creating a corrosion-free system. You can easily connect or make adjustments to the tee using hand tools. As the nut is tightened, the back ferrule moves the front ferrule to create an airtight seal. This design also protects against vibration stress. Stainless steel provides durability and strength and is aesthetically pleasing.