The Ilsco GBL-4DBT are tin plated copper grounding lug connectors with stainless steel screws. They are rated for direct burial. In 2013 Ilsco grounding lugs received UL certification under UL2703 standard and are compliant with all NEC requirements for roof and ground mounted photovoltaic systems. The GBL-4DBT comes with a stainless steel hex screw, and a 10-32 thread forming screw & lock-tooth washer (not shown in picture).
Ilsco part No. GBL-4DBT