Exterior/ pool gate combination locks?

I'm trying to help my parents lock their exterior pool gate with a combination lock, but it doesn't appear there are any normal battery operated locks designed for the exterior? By exterior, I mean both sides being exposed to the elements? You can find a lot of mechanical locks that are $400+, but you can get a Schlage for $100 for interior, seems crazy there is not a better basic exterior option that is battery powered? The problem with the mechanical is you have to basically take them apart to change the code from what I've seen.

Any suggestions or options? They are trying to give some contractors limited access to their backyard through the exterior.