The Penroc Lava Rock is designed to replace the lava rocks on your gas BBQ - giving you the authentic and unbeatable aroma of a charcoal barbecue. The distinctive design of Penroc allows the fat from your cooking to simply roll off, preventing messy clogging and minimising the chance of flaring. Penroc is manufactured using slate and ceramic with a mixture of fine oakwood particles and purified charcoal. The mix is then hardened to it's distinctive shape for long lasting and hard wearing use.