Typically, SLAs are between companies and external vendors, but they can also be between two departments within a company. Pro tip: When sharing a tender, the customer must clearly define the expected service levels. This will help filter suppliers who lack skills, staff. B multilingual or 24/7 coverage. Pre-disclosure of the minimum service levels required saves both parties time and effort. Service Availability: The time the Service is available for use. This can be measured by the time window, by which, for example, between the hours of 8.m and 6 P.m. an availability of 99.5% and at other times an availability of more or less is indicated. .