You might argue that the Paul Wertico Special Quintet, established by Wertico in 1990, needs no identifying adjective--that it's been "readily distinguishable from others in the same category" (Merriam-Webster) from the start. With Orbert Davis's cool, crisp trumpet leading the way, the band displays a breezy professionalism without masking its impassioned respect for the mainstream jazz library of the mid-to-late 60s, which is the stylistic underpinning for everything it plays (including the uncluttered compositions of the band's bassist, Eric Hochberg). And the players' willingness to apply their experiences in vastly different jazz styles to the band's sound gives it an edge that's lacking among so many of the neo-boppers. So what makes Wertico's quintet so special this time around? The fact that the main ingredient is guest pianist Lyle Mays, Wertico's bandmate from the Pat Metheny Group. Mays has a silky touch and the ability to seemingly surprise even himself when he improvises. He hasn't played much straight-ahead jazz since his days with the Woody Herman Band, but you can anticipate the same sort of luminous reexamination of the genre that distinguishes Wertico's own playing. This edition of the band also stars saxophonist Steve Eisen; since he belongs to another of Wertico's bands, the fancifully named Strabagander, his appearance will allow Wertico to dip into that group's highly original repertoire as well. Saturday, 8 PM, Green Mill, 4802 N. Broadway; 878-5552.