Norton Brass Rattler spoons are made to cast like a bullet. The rattle chamber is made from real pistol brass. The 5/8" is from 38 cal., and the 7/16" is from 32 cal. Both transmit loud clicking soundwaves similar to frightened shimp, crabs and crawfish combined with the bait fish rainbow finish provoke savage attacks from redfish, specks, bass, and other gamefish.