This water bottle holder was deisgned to be used on a backpack where the shoulder straps DO NOT detach from the body of the backpack. If your shoulder straps detach from your backpack, you can use our other watter bottle holder that has continuous straps on the eater bolle holder. This water bottle holder is designed to carry a 1L Smartwater bottle (2.75" diameter). The holder easily attaches (see 'Install Video') to your backpack's shoulder strap with a snap hook at the top and three rear detachable straps to provide stability when hiking. Top and bottom loop pull tabs make it easy to insert and pull water bottle out of the holder. Ultralight weight of 0.5 ounces. Holder dimensions are 4” x 9.5”. The design, material, and stitching used to produce this holder ensures it’s as functional, durable, and ultra-light weight as possible. A little about the material we use: The front and back panels are made of super durable 100% nylon mesh. The elastic straps, cording, and buckle are made from high-strength nylon. Our craftspeople use reinforced stitching techniques to ensure extreme durability along each seam. If you prefer to have the holder sit approximately 1.5" higher on your shoulder strap and be attached without the snap hook, please watch the Install Video to see how to remove the snap hook and use the lower buckle as the fastener. Please note that your backpack must have detachable shoulder straps as our holders slide around a shoulder strap. Also, you can carry the Smart Water bottle upside down (see photo) as some hikers find it easier to insert the bottle into the holder this way. All of our products have exceptional design, material, craftsmanship, and customer service. They are backed by our 'Forever Guarantee'....our gear is built to last forever, so if you ever have a problem, no matter how old it is, let us know and we'll send you a replacement.