This Jang TD-1 Corn Seed Plate has 8 round holes that are 5/16"(8mm) in diameter. Plate spacing can be adjusted from 4-10" apart depending on sprocket settings. Seed plate holes allow for individual seeds to pass through for accurate seed drop and spacing. Made from anti-abrasion plastic to prevent build-up of static electricity that causes seeds to stick together. This item is shipped directly from our supplier, please allow 7-10 business days for delivery.