Our I-Bolic technology is a 1.5 lb EPS foam core with a 18mm high density foam stringer in the core, 16mm high density foam parabolic rails to control flex, and a 5mm high density foam springer on the bottom. Paired with our standard fiberglass lamination, on the deck it has a 3mm high density composite deck skin on the deck sandwiched between the double 4 oz E fiberglass cloth layers, and also has double 4 oz E fiberglass capping the bottom.