This tee has a curved center section. In drainage systems, it is primarily used to connect horizontal drains (including fixture trap arms) to vertical drains. The center connection is generally to the pipe leading to a trap (the trap arm). It must not connect a vertical drain to a horizontal drain, because of the likelihood that solids will accumulate at the bottom of the junction and cause a blockage.
BBB - UPVC PIPES & FITTINGSSAE - CATALOGUECEW SIN PLASTIC - CATALOGUECHIN LEAN - CATALOGUE
The female threaded tee connecting the main pipe, leading to one branch, distributes the flow in the main pipe and the branch pipe of the same diameter.