This is the Time Timer I throw in a bag to take with me.
General: It's a Time Timer timer. It's intuitive and helps visually track time. The colored disc is attention grabbing, making it harder to forget the timer is there. I wish the alarm on/off state were indicated on the front.
Original 3" specific: I prefer the Time Timer MOD. I think the Original 3" sits just a touch too upright, and I prefer the knob style timer adjustment. That said, the Original 3" is a little more compact than the MOD, and the hinged plastic cover on the Original 3" prevents the dial from being bumped, which can set other models' alarms off while carrying them in a bag.