# Trading Mechanism Trading functions using an underlying central limit order book for each market / underlying asset. #### Placing Orders On an insert order instruction, the public key for the underlying market for that particular product, as well as the price, size and side of the order must be passed in. For more details about specific order types see [Order Types](/zeta-protocol/learn-how-to-trade-on-zeta/order-types.md). **Tick sizes** Orders can only be placed with a minimum tick size on insert. For orders which are below the minimum increment value, they will be rejected. Minimum price fluctuation for all contracts - [see trading mechanism](/zeta-protocol/trading-specifications.md) **Tick sizes** Minimum trade lot size for all contracts - [see trading mechanism](/zeta-protocol/trading-specifications.md) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.zeta.markets/zeta-protocol/exchange-architecture/trading-mechanism.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.