Saige's M4.5 x 65 Carbon Steel Self-Drilling Screws are perfect for securing timber joists. Featuring a dual thread design, these screws effectively pull the decking down while lifting the joist for a tight fit. While they are specifically designed for composite decking, they can also be used with timber decking. Pre-drilling is required, and each box includes pre-drilling and countersinking tools, along with a 50mm star drive bit. Available colors include charcoal, coffee, driftwood, and grey.