A rule specifying the maximum number of times an ad can be shown to a user over a particular time period.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v26/services/reach_plan_service.proto)

| Fields ||
|---|---|
| ## `impressions` | `int32` Required. The number of impressions, inclusive. |
| ## `time_unit` | `https://developers.google.com/google-ads/api/reference/rpc/v26/FrequencyCapTimeUnitEnum.FrequencyCapTimeUnit` Required. The type of time unit. |