Round Shouldered Fitting Instructions
Begin by measuring the cross section at the bottom from left to right.
This is what is know as the width.
Then measure from the bottom left all the way around the bend, to the bottom right.
This is what is known as the curved edge.
It is advised that you trim a couple of small v's around the rounded corners on the back of the seal.
This will prevent the seal from kinking up and allow it to sit flat against the door.