The ultimate Self Drilling Woodworking screws with almost 35 years of unsurpassed performance and long term reliability. Available in (7) sizes of Tech7 Stainless Steel Self Drilling screws designed for overall strength during and after installation. Recommended for use in outdoor applications where corrosion spec's dictate stainless steel must be used and where anticipated loads require increased head size for long term strength performance... See full description for further details