hidden lugs? or exposed lugs for wheel lock

I plan to put wheel locks on my new car. But I saw two differnt locks. One is Chrome-Plated For Exposed Lugs the other one is Hidden Lugs, Non-Decorative. What's the differences between these two?

The Chrome lugs are for wheels with exposed lugs that don't have wheel covers. The others are for steel wheels that have covers. There is no difference as far as size.