This product makes a huge positive impact to my backpacking - I can now take periodic sips of water on the move without having to carry a water bottle in my hand or on my pack straps. Fits a smart water bottle perfectly and hose is plenty long to reach either side pocket or even rear pouch. Air hole has a small relief valve in it to prevent water from spilling out and to keep foreign material out of your water. The hose disconnect allows you to change out the cap and straw from your empty bottle to your full bottle. The clip to connect hose and bite valve to pack strap is helpful but kind of flimsy and prone to falling off my pack strap - would like to see that proved. Only reason I give this 4 stars. Product is well made and rugged. I would recommend this for anyone who has trouble reaching the bottles in your pack pockets without having to take off the pack.