The gravelking slick is fast because the tread is thin but the casing isn't particularly supple. Gotta rely on good sealant for reliability with them, but you'll get 3-4k before they are down to treads. Contrast that with the Rene Herse versions also made by panaracer which are faster and more robust in the tread area with a thicker rubber and much more supple casing and no? puncture layer.