Surge protectors are usually rated in joules, which are a way to measure energy, and in essence, the more joules the better. For computer systems, 1,000 joules or more is recommended. This joule rating gives you a sense of how long the device can protect against surges and spikes.
Most commercial motor vehicles in Wisconsin require a USDOT Number and it must be provided at the time of registration. If you are required to have a USDOT Number, and cannot produce the number for verification, your vehicle registration application will not be processed until a valid number is provided.
The requirement to use N on aircraft operated within U.S. boundaries did not come about until 1948. In 1929, the Air Commerce Act was amended to modify the identification number convention. Under the new plan, a combination of three numbers and an alpha suffix of: E, H, K, M, N, V, W, or Y was approved.