> [!NOTE] > **Note:** Key-value segmentation is available only for AdMob Pro users. For details, reach out to your Google account manager. Key-value segmentation lets you define custom targeting to segment users through an ad request. For details on key-value segmentation, such as adding a key-value pair in the AdMob UI, see [Add key-value segmentation to a mediation group](https://support.google.com/admob/answer/14916631). This page guides you through implementing key-value segmentation when configuring an ad request using Google Mobile Ads Unity Plugin. ## Before you begin To set up key-value segmentation in your app, you must first [add key-value segmentation to a mediation group](https://support.google.com/admob/answer/14916631). ## Attach key-value pairs to an ad request After setting up your custom key-value pairs in the AdMob UI, attach the pairs to an ad request in your application. 1. Create a key-value pair object representing your custom targeting data. 2. Set the `CustomTargeting` property of the ad request to this object. The following example covers the previous steps to segment users by duration in an app: ```c# var daysInApp = 1; // Step 1: Create the key-value pair dictionary with custom targeting data. var customTargeting = new Dictionary { ["USER_DURATION"] = daysInApp < 3 ? "NEW" : "MATURE", }; // Step 2: Create an ad request with custom targeting. var request = new AdRequest() { CustomTargeting = customTargeting, }; ``` ## Test the key-value segmentation setup To test your implementation on custom key-value pairs, send an ad request and check the [response info](https://developers.google.com/admob/unity/response-info.md.txt#response_info) object. Verify that the value of the `mediation_group_name` field matches your expected mediation group name. The following example verifies a mediation group name in the ad response: ```json { "Response ID": "r6_DZtitA8Gi2OMPyKeksAI", ... "Response Extras": { "mediation_group_name": "Mediation group for new users" } } ```