The Large Water Hopper is made of precoated galvanized steel in 0,6mm thickness. Because of the high quality steel it will age in the same way as all the other products in the system and no difference in design will occur. Lindab Magestic carries a 10 year warranty. Magestic – The King of Galvanised Gutters, an improved galvanised steel with a strengthened magnesium zinc alloy coating offering the highest surface protection of any metallic coated steel.