The B designates the series of engine, B-series was used in civics, integras, and crv's. The 16, 17, 18, and 20 designate the engine size 16 = 1.6 liter, 17 = 1.7 liter, etc. and JDM designates that it is from the Japanese Domestic Market (for use in Japan), or USDM US Domestic Market. US and Japan motors are slightly different in the way they are tuned for emissions.