Simpson 0.390 x 4" Strong-Drive SDHR COMBO-HEAD Screw Blue Zinc Grind / Sand / Polish (2) backplates - two backplates

(2) backplates - two backplates make up one complete connection

38/12 reflects Simpson Strong-Tie's commitment to precision forming

A dedicated 3-phase electrical supply is required for installation

preserving the material's integrity even in aggressive environments

T25 6-lobe drive for secure

Simpson 0.390 x 4" Strong-Drive SDHR COMBO-HEAD Screw Blue Zinc Grind / Sand / Polish (2) backplates - two backplatesThe Simpson Strong Drive SDHR Combo Head Screw is a heavy duty structural fastener engineered for cross laminated timber construction, mass timber assemblies, and general interior applications. Built with a partially threaded shank and a robust 0. 390 in. outer diameter, this blue zinc coated screw is purpose built to draw structural members tightly together while delivering exceptional connection strength in engineered wood and modular construction