# Specifiers **Specifiers** provide a consistent and descriptive way to define additional parameters that uniquely identify a market.\ In the Unified Feed, specifiers are sent as **key/value** pairs separated by the `|` symbol.\ For example, in a cricket match, the specifier string `overnr=5|total=2.5` indicates an over/under bet with a total of 2.5 runs placed on the 5th over of the match. You can find all market descriptions at: `/descriptions/{language}/markets.xml` ```xml ``` #### Extended Specifiers In addition to the [specifier](https://docs.sportradar.com/uof/introduction/key-concepts/specifiers), some markets have an extended specifier attribute to add an extra layer of information. This extended specifier is NOT a unique way to identify a market, but simply more extra information added to certain markets: XML example ```xml ``` Please note that not all markets have extended specifiers, and this attribute should not be used to identify a unique market. Only the market ID and the normal market specifier should be used for this purpose. ### Match Market Specifier For each H2H market an "**artificial**" match is created that contains the details about competitors from H2H, etc. The market on `sr:simple_tournament` contains the specifier that contains the reference to the "artificial" match called the match market specifier. This is represented by `sr:matchmarket:1111111123` Consider ***sr:simple\_tournament:1910***** (H2H - Race - Drivers for Formula 1)** and market **539** with specifier `sr:matchmarket:18377109`*. Y*ou can see that it reference to match **18377109**. If you check fixture for that match it has the following properties: * Tournament: sr:simple\_tournament:1910 * Scheduled at 2019-06-07T14:00:00 * Competitors: Hamilton, Lewis vs. Bottas, Valtteri **Special note for Formula 1** Until now `sr:simple_tournament:1910`, `sr:simple_tournament:1911`, and `sr:simple_tournament:1944` were used as event id for head2head markets. Instead of referencing head2head markets to the mentioned `sr:simple_tournaments`, we will from now on use `sr:stage:` as event id for those markets in Formula 1. Example from the previous Formula 1 season using sr:simple\_tournament ```xml ``` Example from the upcoming Formula 1 season using sr:stage:\ ```xml ```