The new Mueller Adjusta-Coil meter box grade adjusts without adding rings. Twist the top, lift or lower to a new position, and twist again to lock. Available boxes adjust in 1-in. increments over standard 36-in.-to-42-in. and 48-in-to-60-in. ranges as well as others. It has features of the Thermal-Coil meter box, including options for single and tandem meters, locking and non-locking lids, enclosed bottom and more.