Lightly resin bonded mattresses (LRB) consists of fine fibers spun fromlected rocks melted at high temperature and bonded with a thermosetting resin. They are Machine laid fiber lay pattern and are baked to form mattresses of predetermined density and thickness.

Mattresses are then chopped slit and stitched to specified dimensions. LRB has excellent stability. It has controlled thickness and density resulting in predictable heat losses