Casio F-108WH-2AEF

Sharing the same accuracy specs of the infamous F91W, the F108W sporting a slightly larger workings and casing puts out a 

It is a bold claim, 

My test started on the 16th June 2014 and finished 19th July 2015. Each time I synchronised it with eBay time. The result - the watch gained 4mins 15secs in that time, that's 256 seconds in 398 days