The high energy content of the briquettes allows comfortable and economical heating. These Briquettes are made from mixed sawdust of softwood and hardwood. RUF is made on an extruder press which prevents this briquette from expanding when burning and therefore gives a long-lasting burn time, especially in a wood burner. A great supplement to a real wood fire or can be used independently produces very little smoke and is easy to light with a small amount of kindling.