New Ziploc brand Slider Freezer Bags helps provide unbeatable protection with new Power Shield technology. With a new more durable film and an expandable bottom, Ziploc brand Slider Freezer Bags outperform the competition in strength and reliability**. Less freezer burn means less wasted food and more money saved. **Bag film tested using ASTM D1709 Dart Drop and ASTM D2582 PPT