Armstrong Ceilings Suprafine 20 Pack 144 in Galvanized Steel Ceiling Grid Main Beam Roof Shingles For smaller rail sizes we For smaller rail sizes we recommend securing with screws or zip ties under railing for added stability (screws not included) California residents see Prop 65 warnings 144 in x 9 16 in x 1 11 16 in Rotary stitched web for additional torsional strength and extra stability Hot dipped galvanized coating inhibits red rusting better than electrogalvanized or painted systems Heavy duty load performance 240 Lft per carton (20 pieces per carton) Easy to cut and field modify to suit job conditions using standard tools White colored capping SuperLock™ main beam clip is engineered for a strong accurate alignment confirmed with an audible click