The Water Hammer Arrestor is used in a mixture of residential, commercial, and industrial water line applications for protection against over-pressure during surges following quick valve closure. Excessive pressure surges are absorbed by the pre-charged air cushion that is permanently sealed within the water hammer arrestor. The 1260XL can be installed within a stud bay, eliminating the need for an access panel. Features include all copper and brass external construction, a temperature range of -40°F to 212°F, and a maximum transient pressure surge of 150 psi following quick valve closure.