U-Bolt Mechanical Tee mainly works by self-sealing with mechanical force and pressure:
Drill a hole of specified size (commonly 30mm) on the main pipe. Put the EPDM sealing gasket onto the hole. Wrap the U-shaped clamp with the branch pipe around the main pipe and secure it with U-bolts and nuts. When tightened, the pressure-responsive gasket is compressed to form a seal.