Prof Outdoors—billed as “the biggest show in the history of Prof” year after year—has reliably become a kind of late-summer mini-Soundset, and the 2017 lineup may be the event’s most well-rounded yet. Prof, the titular Minneapolis rapper and Rhymesayers/Stophouse Group wildman, isn’t the only long-established Twin Cities royalty slated to perform. PO4 will also feature Doomtree spinoff group Shredders (P.O.S, Sims, Lazerbeak, and Paper Tiger), who emerged this summer with an aggro debut EP and a follow-up single that premiered on HBO’s Ballers. Also performing will be a pair of out-of-state acts: the Underachievers, the Brooklyn psych-rap mystics whose recent Renaissance LP has been unjustly overlooked, and Mac Lethal, the Kansas City, Missouri, native who’s best known for the viral freestyles he’s uploaded to YouTube throughout the 2010s. The PO4 bill is rounded out by Minneapolis’ young Finding Novyon (returning to the 612 after recently relocating to L.A.), plus St. Paul native and new Stophouse Group signee Cashinova.