I heard someone using below phone on the Papa system yesterday; its an Android with 440MHz radio! The Amazon link claims it can w/stand immersion in 2 meters of water for 2 hours and 1 meter of concrete for 24 hours! (I wonder how they got it out of the concrete after the concrete set up?). Also states they tested it by driving nails with the screen (doesn't say if it passed or not)!

I guess you can claim anything when selling on Amazon from China.

https://smile.amazon.com/Ulefone-Armor-3WT-Waterproof-Smartphone/dp/B07X352VS3?sa-no-redirect=1