> [!CAUTION]
> **Caution:** This documentation is for Google Ads API **v24** . The latest active version is [**v26**](https://developers.google.com/google-ads/api/reference/rpc/latest/FixedCpmTargetFrequencyTimeUnitEnum.FixedCpmTargetFrequencyTimeUnit).

An enum describing the time window over which the bidding is optimized to meet the target frequency when using Fixed CPM bidding strategy.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v24/enums/fixed_cpm_target_frequency_time_unit.proto)

| Enums ||
|---|---|
| ## `MONTHLY` | Optimize bidding to reach target frequency in 30 days. |
| ## `UNKNOWN` | Used for return value only. Represents value unknown in this version. |
| ## `UNSPECIFIED` | Not specified. |