Lufkin 1066D Red End Engineer scale rule by is used widely by site engineers, road builders and any company using grade elevations. 100th's and 10th's on one side and the inch scale on the other side. Lufkin 1066d red end rule is 6' in length. Lufkin 1066D red end engineer rule is often referred to as the "Rugged" because of the extra thickness of the wood.