We prefer the Ulefone Armor series of products, see link to that topic, the Ulefone Armor 13 is an older model but is absolutely watertight and has a big battery which is now running as a display.
We also use the Ulefone Armor 24 and the PAD 3 outdoors, even bigger batteries, these are also sunlight readable, can be used with wet fingers and/or gloves, etc.