The clear difference between poor quality bed bug encasement products and our product, is the effectiveness of the zipper. This is the weak link, and a bed bug's primary point of entry and exit, if not designed properly. The scientifically designed and patented zipper technology, known as Zip-Tech TM, truly separates us from the competition. The zipper's micro-teeth are so small that even an infant nymph stage bed bug (almost microscopic) can't get through. This is backed up with an ingenious Belcro security plate behind the zipper head that, once closed, stays closed. And finally, our scientifically engineered triangulation seal above the zipper head keeps it all in place and locked tight, giving you peace of mind in knowing your encasement product from us is on the job!