Accuform, MVTR301VP10, 18" x 24" ANSI Warning Safety Sign "Helicopter Landing Area" Plastic Features: Manufactured with 50% Post-Consumer Recycled plastic and is recyclable – code 2 .055" thick polyethylene, matte surface print Impact resistant with slight flexibility Rounded corners and 3/16" mounting holes on most sizes, will be adjusted for larger sizes Service temperature range: -90°F to 168°