Electronic or Mechanical punch code locks for doors on service buildings/sheds. Good products?

Hi all,I’ve got some mechanic shop and storage buildings in a park I just bought and I want to get them secured. Ideally, I would use punch code locks but was surprised to see how junky they looked at Home Depot. Can anyone recommend a product or alternate solution? I could use the hanging locks too with a code. I would like a code solution for contractors to use. I keep some supplies on hand for water/sewer/electrical issues.