Sand Trap Louver is used for separating sand from intake airSTL – GALV. sand trap louver (galv.steel)STL – Alum . sand trap louver (alum.steel)STL – SS . sand trap louver (stainless steel)– Holes 19 mm dla.at bottom casing only– Bird screen 12 mm x 12mm x1 mm as a standard, other sizes available on request..