Casio sites don't seem to be able to agree. I've seen 64g, 66g, 68g, and most interestingly, the following (on the USA site):
Size of case/total weight
DW6900RC--53.2 x 50.0 x 16.3mm/75g
DW6900MC--53.2 x 50.0 x 16.3mm/68g
What does 'RC' and 'MC' mean in this context? Resin case / metal case? But why would metal be lighter?
Anybody got a 6900 and some laboratory scales to hand?