The Otter Cage is made from a single sheet of lightweight 5052 alloy. The arms of the otter cradle your water bottle nice and tight like a mama otter floating on her back with her pup. We donate 10% of the profits from the Otter Cage to organizations that protect wildlands & wildlife, organizations like Oregon Wild. SPECIFICATIONS - 10% of profits from the sale of this cage will be donated to organizations that protect wildlands & wildlife - Constructed of 5052 alloy - Includes two stainless bolts for installation - Weight: 57g (2 oz) - Lifetime PDWarranty