Heavy Duty Reinforced Thread Nylon Spiral Expansion Anchors High Grip Screw In Wall Fixing Plugs for Hollow Brick Block Product Description The product is a heavy-duty screw-in spiral expansion anchor specially engineered for medium to heavy load applications on hollow brick, hollow concrete block, and perforated clay brick substrates. It features a thickened nylon sleeve with reinforced double-spiral thread profile that provides significantly enhanced expansion force and