Casio Men's Wave Ceptor Solar Radio Watch Multi-Band 6 WVA-M640B-1A2JF vs Casio Men's Wave Ceptor Solar Radio Watch Multi-Band 6 WVA-M650-2AJF

Both are Casio Wave Ceptor solar radio watches with Multi-Band 6, so timekeeping accuracy and never needing a battery are shared. The WVA-M640B-1A2JF is the dressier pick: a stainless steel case, black IP finish, gold accents and a urethane band, at 43.5 mm and 45 g. The WVA-M650-2AJF is the more rugged, function-heavy pick: resin case and strap, 48.8 mm wide, 14.5 mm thick, with 48-city world time, 5 daily alarms, stopwatch and timer. Owners of both praise the radio sync and solar charging; the M650's larger resin body and curved resin glass feel more sporty and scratch-prone than the M640's steel.

• Choose the WVA-M640B-1A2JF if you want a slimmer, steel-cased watch that looks dressier and still runs on solar with radio sync.
• Choose the WVA-M650-2AJF if you want the bigger dual-LCD display, five alarms, stopwatch and timer in a tough resin body for daily sport use.