Casio F91W vs. A158 Watch Review. What's the Difference?

When researching Casio watches, I was unclear on the differences between the F91W and A158. I ended up buying one of each to compare, but I thought it would be helpful for others to know the differences.

Casio F91W and A158 Case and Details

The main difference between the two models is the case. The F91W is made of resin, while the A158 is polished steel. The dimensions are close enough that you wouldn't notice a difference.

The markings on the faceplates are different between the two, but the functions are identical. The LCDs appear to be the same as well.

Wearing the Casio F91W and A158

The A158 is so thin that it almost disappears on the wrist, although it weighs more than the F91W. For an all-metal watch, it's comfortable. The appearance is also more versatile than the plastic F91W.

The buttons are easy to operate. Despite the small size, the positive LCD is also easy to read, even at angles.

Casio F91W and A158 Strap, Bracelet, and Replacement Straps

Both watches have 18mm lugs. The F91W secures its strap with a pin that must be pressed out, while the A158 uses traditional springbars (and has non-drilled lugs).

StrapHabit TQ18 Q Timex straps fit both.

Casio F91W and A158 Movement (Module)

Both watches use Module 593 because the A158 says "Lithium" on the faceplate; I assumed that it would have an upgraded battery. Casio, however, lists the battery life of both at seven years.

Both are easy to set and adjust without instructions. They feature a time, day, and date display, an alarm, and a stopwatch. Both appear to use the same dim green backlight.

Casio F91W and A158 Conclusion - Which should you buy?

The choice really comes down to whether you prefer the appearance and feel of metal or plastic. I would buy the A158 to wear for its versatility, or the F91W if you value low weight and plan to bang it up.

Casio F91W and A158 Specifications