Key Management - Waterproof

[Sharee Mason]

We have a property management company for beachfront rentals.  Our outdated key system has a branded key tag with a piece of tape and sharpie label for the property number.  It looks bad.  I want to revamp the whole thing, keep the branded key tag, and have a way to label each tag that looks professional and holds up to the elements.  Our keys frequently travel in beach bags, get wet, and get roughed up by sand.  Can anyone recommend a labeling system that looks professional?