The watertight roll down closure makes the bag fully a djustable. A D-ring on the clip makes it easy to clip the Kodiak Sac to your harness, your backpack or a rope. The Kodiak Sac is very lightweight and compact. I have found it to be very reliable. Under the demanding canyoneering circumstances, I have been able to count on the Kodiak Sac to keep my things dry.
Prices vary by model, but are very reasonable.
The Black Canyon dry bags are slightly heavier nylon than the Kodiak Sac. They are also somewhat less packable than the Kodiak Sac as the nylon is a little stiffer. Weights and sizes vary according to model. I used the Black Canyon 30 primarily to keep my clothes and sleeping bag dry on backpacking and canyoneering trips. The heavier nylon seems a little more durable, and I wanted to make sure my essential items stayed dry.