This thing wasn't designed well. Maybe they tried to do too much with it. The programming is very complex and impossible without the instructions (and the instructions are not written well either). Now after my final use before I return it, the battery and holder slide out as I run and resets the program, and erases everything I was trying to track.The disappointment with this unit will definitely affect my decision to buy anything from Oregon Scientific.Conclusion: DO NOT BUY THIS UNIT!!! Even if you get it for free, the time and aggravation are not worth it and will not do the job intended. If I could give it less than one star I would!!Here is a link that also shows the manual.[...]