American Keith Knight and Canadian Don Alder aren’t known as the “Extreme Guitar Duo” for nothin’.

Here’s what the Picque News Magazine has to say about Alder, in particular: “Alder can make a single instrument sound like a four piece band. The guy’s like the acoustic Hendrix!”

The State Newspaper of Columbia, S.C., is equally enthralled by Knight: “Keith Knight’s jaw-dropping, fingerstyle playing puts him on the bus with pickers like Chris Proctor and Leo Kottke.”

And bearclawmusic.com is giddy about any performance by the duo: “Treat your audience to a great evening of guitar playing, singing, storytelling with monster players Keith Knight and Don Alder. It promises to be an unforgettable event your audience will be talking about for years to come.”

That’s what’s in store, Friday, at San Juan Community Theatre.

Alder combines fingerpicking with simultaneous percussion on the soundboard, while Knight showcases a versatility on a wide range of guitars and mandolins in each performance. Their collaboration covers a variety of genres, from modern fingerstyle to tapping, Applalachian to delta/ragtime blues and calypso.

Alder is a former winner of the International Fingerstyle Guitar Championships; Knight has shared the stage with The Smothers Brothers and Melanie.

The duo will light up the theatre’s Whitter Stage, beginning at 7:30 p.m.; tickets, $24 adults, $12 student reserve, $5 RUSH. In addition, the two guitar slingers will present an outreach program for island schools, thanks to a grant from the San Juan Island Community Foundation.