I found Hefty shrink bags to be superior to other brands I've tried.1. The zips are red on one side and yellow on the other, when sealed it creates an orange line. It is easy to see if there is any point where the bag isn't sealed.2. The valves only let air out, they are not bi-directional. This means I don't have to keep track of any valve caps or lose suction when I remove the vacuum to slip on the cap.3. The bags are crystal clear and durable.I recommend this product!!!