Tonight the American Flag will open for Guided by Voices and Sloan, but ideally the power-pop duo should perform between the two better-known bands. Since the twosome (which swells to a sextet on stage) combines the elliptical style of the former with the exuberance of the latter, its music would be the ideal segue. Of course, if the band continues to make albums as spry and inventive as this two-CD set, it may soon be headlining.

Like Sloan, the Flag blithely raids '60s pop-rock and '70s bubblegum, yielding some of the most effervescent (and self-conscious) retro-rock since the Pooh Sticks. Yet singer- songwriters Evan Weisblott and Aval Senior's conceptual caprices also recall the offhand, fragmentary work of GBV mastermind Robert Pollard. (The band's "Who Knows Where the Robots are Hidden?" leads into a version of Pollard's own "Tropical Robots.") As song titles like "Giant Giraffes" and "Naval Angel in Danger" promise, the Flag is seriously whimsical. Still, the best of these 22 songs corroborate one song's brash claim that "I'm Pop."

Appearing Friday at the 9:30 Club with Guided by Voices and Sloan.

* To hear a free Sound Bite from the American Flag, call Post-Haste at 202/334-9000 and press 8121. (Prince William residents, call 690-4110.)