I use this talking timer for keeping my Radio Controlled model airplane flights to 10 minutes and I love this for that reason. I would have rated it a definite 5 except for the fact when I first used it for the first several hours after receiving it the unit worked erratically - sometime it worked, and sometime it didn't. Eventually though, it did start working like it was supposed to. I had the exact same timer 12 years ago and worked fine until it finally died this summer. I clamp the unit (nicely built-in clamp on back) to the flight line fence, set the count DOWN timer (timer can count up, or down) for 10 minutes and depress START. It will voice-signal the start of every new minute. During the last minute it will voice-signal every 10 seconds. During the last 10 seconds, it will voice-signal every second which at ZERO will beep or make a few other sounds that you decide to use and can pre-set. Good timer overall as long as it works. Much less expensive that the other sellers of the exact same product - but just because those sellers state "This product is used in the medical or science field" they think they should charge 3 to 4 times the price of this one - for the exact SAME UNIT. Choose comparatively, and choose wisely. This unit that has "Tel-time" at the top of the unit (or "VoiceZone" at the top) at the price I paid in Sept 2020 ($12.95) is the fairest, and THE best deal for a very nice talking timer - whatever you may use it for.