Insert magnet is designed specifically to create free spaces in the precast concrete components for mounting concrete inserts. Through the combination of various materials like rubber, nylon, plastics, steels and epoxy, the standard and customized precast concrete insert magnet is available with almost any geometry and magnetic force to work well in convenient fastening of almost all built-in precast concrete elements like threaded sleeves, electrical sockets, anchor loops, weld-on plates, etc. Insert magnet enables rapid and tight fastening but easy positioning, which improves assembly efficiency, reduces construction costs, and enhances structural stability of precast concrete products.