Thanks for your evaluation. But we need to clarify the facts. 1.The ordering page clearly displays photos of different options. D1, K1, and three different screw in units. The details page also displays the differences between the three units. The options clearly indicate the product and corresponding price. 2. Some customers purchase for maintenance purposes, only requiring a switch, without the need for screw in units. The important thing is that there are three types of screw in units, and we do not know which one the customer needs, so they are listed as models for customers to choose from. Thank you very much for your purchase. Please feel free to contact me if you have any questions.

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