Manufactured from high strength copper alloy with stainless steel screw. UL listed and CSA certified for direct burial in earth or concrete. Tested to UL 467. GBL-4DBT and GBL-4DBTH are UL2703 Listed. Lay-in feature for ease in installation. For copper conductor only. Rated for grounding and bonding. Green color, universal to identify ground aids in visual inspection. T - Tin Plated. H - Stainless Steel Hex Head Screw.