Good for playing against the clock, especially the stop timer function. The clock description on Revain is terrible and doesn't cover most of the good things about timers. But don't try to use the clock at night. The D and E keys must turn on the display backlight for night use. The D button doesn't work, which is a shame because the E button is more difficult to use. The E button turns on a COMPLETELY USELESS LIGHT. To even notice the light is on you have to be in complete darkness, and the…