GSHOCK GA-900-4A This means that the watch

This means that the watch no longer beeps when switching from one function to another

LED backlight for the digital display (Super illuminator

Auto Run Timing Start

Case depth is 9mm

GSHOCK GA-900-4A This means that the watchSpecifications Case bezel material: Resin Resin Band Shock Resistant Mineral Glass 200 meter water resistance LED light (Super Illuminator)Selectable illumination duration (1. 5 seconds or 3 seconds), afterglow Hand shift feature (Hands move out of the way to provide an unobstructed view of digital display contents.) World time31 time zones (48 cities + coordinated universal time), daylight saving on off, Home city World time city swapping, One touch