SharkBite 1/2 in. MIP Traditional Water Hammer ArrestorProvides maintenance free, continuous protection against water hammer. Adaptable for multiple applications and can be positioned vertically or horizontally. Simply cut into the line and install the fitting. Features and benefits: Can be installed in wet lines. Approved for behind the wall applications with no access panels. Size AA Water Hammer Arrestors, used for point of use residential appliance applications.