hi. i am very sorry. i just read you message. imo, gdf-100-1b is better than gdf-100-1a. the colour is more attractive than gdf-100-1a. gdf-100-1a looks boring. although the screen is negative, you can easily read the time. the illumination of gdf-100 is really good. by the way, i will send you photos of the g-shock.