*PLUMBERSSTOCK EXPERT* responded:
Hi, Thanks for visiting PlumbersStock.com and for your interest in the MetalFab 6M6SY3 6" B-Vent 6X6X3 Swivel Wye. Yes, you are correct. The side inlet is the 3" size. If you are ready to order just click add to cart, or if you ave additional questions, you can contact one of our friendly customer service representatives for more information. They can be reached @ 435-868-4020 or through e-mail @ firstname.lastname@example.org.