Simpson Strong-Tie SDCFC Timber-CFC Screws are structural fasteners designed for cross-laminated timber (CLT) construction, mass timber construction, and general interior applications. They provide extra strength for demanding applications that require large-sized structural members. The yellow zinc coating is intended for interior, dry applications only. Common applications include beam reinforcement, wall-to-wall, floor-to-floor, support beams, butt joints, and splitting reinforcement.