The MARKSMAN predrill bits are sized to compliment Edge hidden deck screws. Predrilling is recommended on hardwood and capped composite boards to eliminate splintering and splitting. Each driver bit is designed to fit your drill and is designed with a shoulder to achieve the right depth. The MARKSMAN system makes it easy to predrill your deck boards. Simply set the MARKSMAN tool, predrill your hole, drop your deck screws in each fastener slot and drive. The CAMO MARKSMAN system hides your deck screws on the edge of the board. By shifting the fastener location from the deck top to the edge of the deck board, you are left with a fastener free deck surface that is less prone to splitting and cracking. Edge fasteners are hidden deck screws designed for ANY wood or composite deck top and any square or grooved board profile.