Industrial-grade Boxed Expansion Anchor Screws. Standard sizes are in ready stock with fast delivery, and we provide non-standard Custom Boxed Fasteners with personalized size, material and package. Made of high-strength carbon steel and stainless steel, these Boxed Anchors feature powerful anchoring force and excellent shock resistance. Packaged with moisture-proof sealed boxes for easy storage and distribution, they are widely used for concrete fixation, bracket installation and heavy object mounting.