First Alert SCO2 Combination Smoke & Carbon Monoxide Alarm w/ 9V Battery $12 Walmart has *First Alert SCO2 Combination Smoke & Carbon Monoxide Alarm w/ 9V Battery* (1039935) for *$12*. Shipping is free w/ Walmart+ (free trial available) or on orders $35+, otherwise select…

LPT: Always keep extra 9v batteries on hand. Don’t be me, who had to listen to a smoke detector beeping, because it’s 11pm and it’s battery just went low. I know it’s pretty basic, but you can forget the basics sometimes. submitted by /u/Im_Dubaya