This valve is used but in good condition.  I am not sure exactly how this is supposed to be measured or identified but  on one side the inside dimension is about 1-1/4" and on the other side it flairs out a little to have a 1-5/16" ID.  The flanges are about 2-3/16" outside to outside.  This does not have a model number on it.

S351-4

fdk 80915238