He is also pretty unique and distinguishable in some of his setups. He plays this Dobro 12-string monster with a pickup as if it were the simplest guitar to slide around with.
Listen to it here in Walkin' Blues:
Another distinguishable innovation of his is the nylon strings setup. The nylons on his Martin acoustic give his sliding a warm sound unlike anything else I've heard:
Finally, one of the things I like about Roy is he often plays in open E which is my tuning of preference also.
I'll leave you with a Roy Tip for beginner sliders:
"The most important thing to remember is to always have fun. Don't let it become laborious."