Gary Smyth
I have no experience with this hammer, but here is the description.

The Stanley 22-Ounce AntiVibe Framing Hammer features a one-piece double-forged steel head and handle for superior swing and greater durability. Its patented tuning fork design reduces harmful vibrations three-times more than conventional one-piece forged steel hammers. The unique grip design is great for both framers and nail hammers.
Made with the professional and serious DIYer in mind. View the details under Stanley AntiVibe. You can also learn more about AntiVibe technology.
Its patented ergonomic handle with a rubber grip molded directly onto shaft is designed for multiple grip positions and is specially textured for improved performance even when wet. The grip is flared at the end to help prevent the hammer from slipping. The hammer comes with a manufacturer's limited lifetime warranty.

About Stanley AntiVibe Hammers
Stanley AntiVibe hammers are made with the professional and serious DIYer in mind. Made of one-piece double forged steel head and handle for swing and durability, the hammers feature a patented tuning fork design that helps reduce harmful vibrations. The ergonomically designed handles, with the rubber grip molded directly onto the shaft, allow for multiple grip positions. The handles also have a specially textured grip for improved performance in wet conditions and an enlarged handle design that helps reduce gripping fatigue. A specially designed head shape provides for better balance and a larger "sweet spot."