22 mm stack, 5 mm drop. Enough protection and stability to get through a marathon, but not so much that racing a hard 5k feels awkward or sluggish. Every other shoe is either super minimalist - 10k, maybe 12k xc (for the streak lt) or super maximal - like its a cardinal sin to run a marathon in less than a 10 mm drop. The new "Super shoes" are awful to my feet. Maybe I ran in flats too long, but a 30 mm or higher stack feels like hell to run in and gives me major ankle issues. God I wish they'd rerelease the adizero rocket.