How to measure waterproof zippers?

Pls refer to below image:

Open End 8TZ CR heavy duty waterproof zippers:

close End 8TZ CR heavy duty airproof zippers

We can accept custom length from 20CM to 5000CM.

We are the best waterproof zippers suppliers in worldwide, the quality is same as ykk waterproof zipper, but the price is better than ykk waterproof zipper.