Does anyone know what size screwdrivers are used for the screws on the watch band and casing (to remove back case to replace battery) for a Chopard women's happy sport white diamonds (5 diamonds) and blue sapphire stainless watch (style 278893-3006)? Thanks!

Hi Chiao,
If you have the watch there and its normal slot type screws when working on a high value watch take watchmakers screwdriver and grind blades down to a perfect fit especially important if gold screws or badly damaged (make sure you clean all the dirt away on the case first), case bands there are many types some you need to hold both sides which need a device with a fixed blade one side and a rotating the other, often a again a normal watchmakers screwdriver, if in doubt don’t risk it take it to a professional much cheaper than the repairs!...