Guess g10150g wrist watch

You really should take it to a jeweler who will have the proper tools to do this without damage to the band or watch, but if you feel you are able and don't mind the chance that you might scratch it.

...you will need a very small (the kind you use for your eye glasses) screw driver -flat head type, and a way to tap (a tack hammer) get a cloth to lay down (dark so you can see the small parts) and work on this surface. Look at the small holes on either side of the band and look for a ( - ) this is the end of the pin that must come out first and this is the direction you will force out the pin from the chamber. To force out the pin you must put the head of the very tiny screw driver on the OPPOSITE end and gently tap the screw driver to push the pin out, once you see a small portion of the pin, pull on it with a pair of pliers, but try not so squeeze it for fear of damage. Repeat at the next pin you wish to remove or 2 or 3 depending on how many you want out. Once you have removed all you need to, hold the links from where you have it separated together and push the pin back up inside the chamber **but make sure it is going back in as it came out---the pin will look sort of like a bobby-pin and the Rounded end goes in first** After you push it in by hand, you can use the tack hammer to tap it back down to make it flush, then use the screw driver to get is just below the surface of the band.

I had the same problem and these instructions were perfect. I had the watch adjusted in about fifteen minutes. It takes some patience, but you can definitely succeed if you follow the directions carefully.