The Strong-Drive SDCF Timber-CF screw is a structural fastener available in a variety of lengths and is designed for cross-laminated timber (CLT), mass timber construction and general interior applications. These 0.315"- and 0.390"-diameter structural fasteners provide uncompromised strength for these demanding applications. The large flat head with underhead nibs provides for clean countersinking. The yellow zinc, fully-threaded screw, with a proprietary unique point, provides fast starts with no predrilling and excellent withdrawal and shear resistance. For interior and dry applications only.