Drones are the replicators' main bulk utility unit. They are comprised of 168 monads working together, compacted into a shape of a quadrupedal insect-like form roughly 18 inches in length. They weigh approximately 6 pounds (or half that much when the base material is mithral). Although drones can harvest and sculpt materials necessary for replication, they are uncapable of refining raw ore and are therefore severely limited in replication speed. Being small constructs, replicators can eat their way through stone and metal and often bide their time within walls or structures where people cannot get to them until they are too many.