I-BEAM RAIL TYPE; EXTRUDED FABRICATED ALUMINUM MATERIAL; 16-7/8 INCH BASE WIDTH; 300 LOAD RATING IN LB; 300 LB LOAD RATING; PARALLEL BASE TYPE; 1 SECTION(S); 1-1/4 INCH ROUND RUNG SIZE; APPLICABLE STANDARD ANSI A14.2, OSHA, UL; RATING TYPE IA HEAVY DUTY