"ITEM IS RECTANGULAR STEEL FRAMES,RETAINING AND MAIN,HOLDING 0.5 IN. THICK ELECTRICALLY HEATED 2-PLY GLASS WITH NEOPRENE GASKET AND ELECTRIAL PLU G AND CLAMP FOR 440 VAC SUPPLYING 350 WATTS PER SQ FT; OUTSIDE DIMS 29.0 IN. BY 21.5 IN.; INSIDE DIMS 25.5 IN. BY 18.0 IN.; 20 BOLT HOLES THROUGH RETAINING FRAME; FOR RAST CONTROL STATION SHIPBOARD"