Outside diameter of the thread. The tolerance range of the "T" dimension will determine the mate between bottle and closure.

Outside diameter of the neck. The difference between the "E" and "T" dimensions divided by two determines the thread depth.

Inner diameter of bottle neck. Specifications require a minimum "I" to allow sufficient clearance for filling tubes. Linerless closures with plug or land seal & dispensing plugs/fitments require controlled "I" dimension for proper fit.

Measured from the top of the finish to the top edge of the first thread. The "S" dimension is the key factor that determines orientation of the closure to bottle and the amount of thread engagement between the bottle and cap.

The height of the neck finish. Measured from the top of the neck to the point where the diameter "T", extended down, intersects the shoulder.