A feature of the Rubicon Market is its ability to optionally match offers in the order book. The most important variable for matching is the matchingEnabled parameter which is determined at the protocol level. When matching is enabled, offers can optionally be automatically matched with offers that are close to existing offers in the order book (+-1 at the 17th integer of the wad) by way of price. If a user does not want their order to be eligible for matching, they should call the offer function with the four core parameters, otherwise providing the pos or matching parameter will allow the order to match. A user can choose to place an offer that has matching functionality into the order book by using the optional parameters of the offer function.