Found this bit of info on the NID of which I own one in 12g
The Field Grade Ithaca NID was one of the classic American doubles. It was introduced in 1925 (replacing the Flues model) and remained the mainstay of the line until the Ithaca Gun Company discontinued all double gun production in 1948. These Ithaca NID Field Grade doubles were solid, workmanlike guns that will still serve modern shooters well, although their stocks usually have more drop than modern stocks. Gun fit is a personal matter and is something to which any prospective buyer should pay close attention. Try before you buy.
The NID was an improved Ithaca boxlock action that featured a rotary bolt locking system and a strengthened frame. NID Field Grade guns typically came with fluid steel barrels suitable for modern shells (but not steel shot), color case hardened receivers with a roll stamped game scene, double triggers, plain extractors, solid rib, and a checkered walnut pistol grip stock. Gauges were 10, 12, 16, 20, 28, and .410.
Today all but the 12 and 16 gauges are primarily of interest to collectors, who have driven the price of the small gauge guns beyond what most shooters are willing to pay. The NID was also produced in many other grades with increasingly fancy features, decoration, and wood. Except for the Grade I, which is similar to the Field Grade, these higher-grade guns are usually out of the affordable price range. Even NID Field Grade guns were produced with variations.
