I have this one and it works quite well. It has a fifty foot range.

The only problem with them is that they don’t detect barks, they detect loud noises, so if you are using them for training, you have to be careful about making noises around them if the dog isn’t barking, tapping them, banging the table they are on, etc. They can also be confusing if they are used for two dogs, because when one barks, they both get “reminders”, so it will take longer for the dogs to associate the deterrent tone with barking.

For OP’s use, they’d be fine.