Currently, the tips on the market are basically made of polypropylene plastic (a colorless transparent plastic with a high chemical inertness and a wide temperature range). However, the same polypropylene, the quality difference will be great: high-quality tips are generally made of natural polypropylene, and cheap tips are likely to use recycled polypropylene plastic (in this case, we can Said that its main ingredient is polypropylene). In addition, most of the tips will be added with a small amount of additives during the manufacturing process. Common ones are: 1. Color-developing materials. The blue gun head (1000ul) and the yellow gun head (200ul), commonly known in the market, add corresponding chromogenic materials to polypropylene (we hope to be high-quality masterbatch, not cheap industrial pigments); 2, release agent. Help the tip quickly disengage from the mold after forming. Of course, the more additives, the higher the probability of an undesirable chemical reaction taking place during pipetting. So it is best not to add additives! However, due to the relatively high requirements on the production process, the tips without additives are rare in the market.