A fitting with a few openings, a wye joins (or produces) branch traces. It's really a waste-fitting tee by which the side inlet pipe enters at a 45-degree angle. A typical wye is often a Y-shaped fitting which enables one pipe to become joined to a different at a 45 http://valvesandfittings12358.blogrenanda.com/105478/the-valves-and-fittings-diaries