"TUBE CAP ASSEMBLY USED ON LOW IMPACT RESISTANCE STRUCTURES FOR LIGHTING SUPPORTS FOR AIRPORT APPROACHLIGHTING SYSTEMS,MODELS ALSF-2 AND MALSR. OVER-ALL DIM,6.25 INCH DIA BY 4-11/16 INCH HIGH. PER FAA SPEC FAA-E-2702;ITEM 5, DRWG D-6155-1, ALSF-2 AND MALSR LIR STRUCTURES, STRUCTURAL CONFIGURATIONS"