These are typically termed protection threads. Whenever you delay US dollars, to the light, the security threads must look like a part of the note, versus becoming printed on it. You will have observed people try this in films and puzzled what they were seeking. The answer is, protection threads. https://escrow-services-in-nigeri36925.bloggerswise.com/40827619/top-latest-five-counterfeiting-money-in-the-usa-urban-news