# Service Levels

Service-level agreement properties such as freshness, availability, and retention targets.

## Service Level Agreement Property {#service-level-agreement-property}

type: ServiceLevelAgreementProperty

| Property | Type | Required | Description |
|---|---|---|---|
| `driver` | string | No | Describes the importance of the SLA from the list of: `regulatory`, `analytics`, or `operational`. Examples: `regulatory`, `analytics`, `operational`. |
| `element` | string | No | Element(s) to check on. Multiple elements should be extremely rare and, if so, separated by commas. |
| `property` | string | Yes | Specific property in SLA, check the periodic table. May requires units (more details to come). |
| `unit` | string | No | **d**, day, days for days; **y**, yr, years for years, etc. Units use the ISO standard. |
| `value` |  | Yes | Agreement value. The label will change based on the property itself. |
| `valueExt` | [AnyNonCollectionType](/docs/reference/data-contract/common-types/#any-non-collection-type) | No | Extended agreement value. The label will change based on the property itself. |