Baby monitor- no wifi

Please tell me your favorite- no wifi- baby monitor. We have the Nanit which has been amazing. But we have had some serious storms and our power keeps going out. I have now spent many nights on his floor because I won’t hear him cry from my room without the monitor like normal. I want an easy no wifi monitor to use mainly for those nights without power or if we go to family’s house and he sleeps in another room. Thank you!