Brass Pipe Fitting, 1 Inch Tee

This tee fitting is designed to fit 1-inch pipes, making it suitable for connecting three pipes of that size.

Brass pipe fittings like this one are sold dry so you can pick the sealant that fits your setup. PTFE tape works fine for most water and air lines. Pipe dope is another solid choice, especially if you're dealing with higher vibration or need a little more gap-filling. Just make sure whatever you grab is rated for the fluid or gas running through your system.