LG GD910 User Manual page 22

Getting to know your phone
2 Hold the watch strap and pull the "A" part of the buckle
vertically.
3 Hold the watch strap and adjust the strap length by
moving the "A" part of the buckle from side to side.
4 To fix the strap length of watch, push the "A" part of the
buckle back to the original location.
5 Close the buckle, you will hear a 'click' when the buckle
is fully closed.
20 LG GD910 | User Guide