For vibration and shock proofing on instruments and radios. Square type 100PL-6 is 1-1/4″ overall x 1″ hole square plate type mount has 6-lb rating, monel mounting plate, non magnetic, with rubber center. Dimension: .141″ dis. base holes for 6-32 screws. .166″ center hole dia. for 8-32 screws.