One of those big pork loins from Costco. About 2' long and about 6" around. I slice against the grain about 1/4" after trimming a bit of fat off. You get at least 7lbs of good slices for jerky, I think my last batch was closer to 8.5 lbs. I used two premade spice mix kits, each one was for 5 lbs. Mad Hunky brand.