In the early days of the Parker Bros. hammerless doubles the 10-gauge guns came at a $5 premium over the smaller gauges in the two lowest grades. So, the 10-gauge version of the lowest grade, PH-Grade was called an NH-Grade and the 10-gauge version of the GH-Grade was called an EH-Grade. From DH-grade on up the 10-gauges were the same price as the smaller gauges.
Accordiing to the tables in The Parker Story there were 1547 NH-Grades made, the vast majority with 30- or 32-inch barrels. Here is one serial 744xx, shipped 16 December 1894, to E.K. Tryon, Jr. & Co. in Philadelphia.