The logs are steel reinforced, and made with lave granules and high heat ceramic refractory that is used to check rocket engines. * Designed to be Used With Vented Gas Log Systems. Highly detailed, hand painted refractory cement logs * For three generations, logs are designed, manufactured in CA USA. * Type: Country BLAZED Oak Gas Logs * Approved Certification is through OMNI TESTING LABORATORIES. Indoor gas logs sets have limited 5 years manufacturer warranty.