Serious Lettering. Seen On the Street By Street Art SF Team on June 29, 2013 Location: Osage Alley @24Street in San Francisco, Ca Artist: Mr EF (EMT) CBS. 7 Seas. Unknown. Tags: 7Seas, CBS Crew, Graffiti Writers, Mr Ef, San Francisco, SF - Mission - Osage Alley, SF - Mission District