"USED ON LOW-IMPACT RESISTANCE STRUCTURES FOR LIGHTING SUPPORTS FOR AIRPORT APPROACH LIGHTING SYSTEMS,MODELS ALSF-2 AND MALSR. OVER-ALL DIM 6-1/4 INCH ID BY 8.90 INCH LG BY 6-5/8INCH WIDE BY 2-1/2 INCH H. PER FAA SPEC; FAA-E-2702;ITEM 7, DRWG D-6155-1, ALSF-2 AND MALSR LIR STRUCTURES, STRUCTURAL CONFIGURATIONS"