All MESH Stock Covers are shipped according to our production schedule when ordered online. Our pricing program will automatically determine if your pool qualifies for a stock cover. Common stock pool cover sizes include covers for 12 x 24, 14 x 28, 16 x 32, 16 x 36, 18 x 36, 20 x 40, 20 x 44, 25 x 50, and 30 x 60 pools. We offer these at such low prices because we already have the patterns, and the sewing of the cover is downright easy compared to customizing a cover to any special specifications.