Philip Stein Classic Round Black Leather Strap Natural Frequency Technology Watch 41-FB-CB The Philip Stein Natural Frequency Technology is delivered to wearers through a metal disk inside the watch that was infused with key frequencies in a proprietary process. When worn, the watch exposes frequencies to the biofield - which is the master energy field that regulates the body's functions - and informs the body to relax and become more resistant to stress. Studies have shown, better sleep, less stress, clearer focus and better concentration, for wearers of Philip Stein watches Brushed stainless steel case (36 mm in diameter, 8 mm thick), Screw-in case-back with sapphire crystal window revealing the Natural Frequency Technology chip Polished stainless steel bezel, Fasion black dial with guilloche center, Silver-tone luminescent hands, Silver-tone Arabic numerals Small seconds sub-dial at the 6 o'clock position, Sapphire coated mineral crystal, Swiss quartz movement Water resistant to 3 ATM/30 meters/99 feet, Black calfskin leather strap, Pin buckle