1)Type: die casting and machined 2)Material: zinc alloy 3)Sizes:1/4*1-1/2 3)surface finished :self color We do the precast concrete in sert more than five yeeas. we have ever done sizes,1/4*1-1/2",3/8*1,3/*1-3/8",1/2*1-1/2,etc.Those were all done by zinc die casting then machined. Coil Insert