Made of Type 304 stainless steel alloy for excellent non-magnetic corrosion-resistant properties. Plates are 0.032 in thick. Brushed satin finish resists fingerprints. Matching stainless steel mounting screws provided. Standard-size - 2-3/4 in x 4-1/2 in, with 1-13/32 in hole, boxed.Excellent non-corrosive and non-magnetic properties for applications needing protection from those elementsExcellent non-corrosive and non-magnetic properties for applications needing protection from those elements302/304 stainless steel alloy contains 18% chromium