either factory, or a GOOD watch repair shop.. not the ones at Kmart or similar. My good pal just had her wristwatch portion of her HRM destroyed ( "oops") as Shopko. I had my same done by the local professional watch shop and it was fine.

They say send them back because a lot of place don't really know what they are doing - department stores and so on. AFter having things messed up by Kmart and Pennys' both, I only go with a real watch shop now.

Irulan