What is the OCO order type?
OCO stands for One-Cancels-the-Other and is a pair of orders. One is a stop-limit order and a limit order is the other one. Both orders have the same order quantity.

How does OCO work?
There is a pair of orders in the OCO order type. If one of them is being executed (for a stop-limit order it means that the stop price was being triggered), the second one will be cancelled. And if one is being cancelled, the result will be a cancellation of the entire pair in the OCO order.

Restrictions on prices
The following rule must be ensured when placing a sell order:

Limit price of limit order > Market price > Stop price of a stop-limit order

Letís assume the last market price was 10. You will have to set the limit price in a sell OCO order on a higher level than 10. And the stop price will have to be lower than 10.

The rule that must be ensured when placing a buy order looks as follows:

Limit Price of limit order < Market price < Stop price of a stop-limit order

In our example where the last market price was 10, you will have to set the limit price in a buy OCO lower than 10, and the stop price that will be greater than 10

To know more follow : How to use effectively the OCO orders on Binance exchange - Binance Wiki