Oil Hydro-mod Casio G-Shock G-7900A-7DR White Moon Tide Digital Watch - FAST SHIPPED WITH USPS Ground Advantage. This is a genuine Casio G-Shock that has been modified with a Hydro mod. A Hydro-Mod Watch is an oil-filled watch, which optimizes functionality, contrast, screen clarity (you will experience a slightly raised appearance and more crispy display), improved viewing angles, and gives you an increased water resistance! The oil I use also prevents the swelling of any rubber seals/gaskets! The oil also adds a few grams to the watch which makes a substantial difference in wrist presence, creating a more solid/luxurious feeling wearing experience. DISCLAIMER: I am not affiliated with Casio or G-shock. This is Genuine, but a used product that has been modified to optimize it. This watch is beautiful and in almost perfect condition. A very unique piece. Please feel free to ask any questions, ask for more pictures, or make an offer!