Instruct: Classify Amazon reviews into positive or negative sentiment
Query: bought as a replacement

I bought this to replace my old co2 detector that would constantly discharge it's battery and beep endlessly for a new battery. Hopefully this unit doesn't end up doing that. The previous detector was from the same brand but a different model; I will post back if this one goes out on me.It's a nice unit and does provide an ac cord that you can plug in 10+ ft away from the actual unit; or you can keep the cord and ac adapter snugged into the back of the unit and plug the entire thing into an outlet. Thats a really nice feature about this model; also the LCD display memorizes the last amount of co2 it has detected so you can always check back to see if you had any leaks.