The joint venture is a perfect way to turn the SR bag into a double bag. It's light weight, slotted for 2 pads and 2 pillows. Quality ykk zippers,easy to wash and well made over all. Been using the SR with the JV for winter temperatures (15°F to 30°F) keeping my large dogs and I warm and it works Awesome for us! No more cold dogs waking me up all night long; instead I now have trouble getting them to leave the tent🤣 Highly Recommended👍👍