DaKine Altitude ABS 25L
Here's what other sites are saying:
After you've checked the avy report for stable conditions, escape the crowds and venture out into the backcountry with the Dakine ABS Vario Cover Backpack attached to your airbag base unit. This durable Cover works in conjunction with the ABS Avalanche Vario Base Unit (sold separately) and easily and securely zips onto the Base Unit with the help of the Base Unit's unique YKK zipper system. Thanks to the Cover's 25-liter size you have more than enough room for all of your avy gear, snacks, spare gloves and goggles, puffy, and other small essentials for a short backcountry tour before or after work.