ACOUSTIC TECHNICAL FOAM POLYETHYLENE K-FLEX K-40X XPE K-FLEX K 41-N K-FLEX K 41-PAG K-FLEX K 40-E K-FLEX K 42-N K-FLEX K 41-PA K-FLEX K 41-PAT K-FLEX K-20X XPE K-FLEX K-30X XPE