The Shieldmaster Tee Cap with Drain fits the 135 as well as the 90 degree Tee Piece. It allows for very easy draining & sweeping of the external system.
You won’t require any additional sealants or silicone to seal all the joints. It has a unique push-fit locking system to make connection and disconnection very simple. The quoted diameter is the internal diameter and the surrounding insulation makes it 2” larger.