The x ray collimator is an electromechanical optical device installed in front of the output window of the tube sleeve of the tube assembly. At present, there are many models and brands of beam limiters in the market. The common brands of beam limiters are Toshiba, Philips and other brands. In China, the brands of beam limiters is Newheek. Compared with other brands, the brand of Newheek bundler is more affordable and can be compared with international brands in terms of quality. Newheek’s brands of beam limiters currently has three models to choose from: NK102, NK103 and NK202. NK102 and NK103 can be matched with 125 kV tube, NK202 can be matched perfectly with 150 KV tube, suitable for different types of X-ray machine.