käyttämät
Käyttämät is a Finnish form that is not part of standard, productive Finnish inflection. It is derived from the verb käyttää, meaning “to use,” but in contemporary Finnish it is not listed as a common dictionary form or as a standard participial form. The usual past passive participle is käytetty, and its plural form is yleensä käytetyt. As such, käyttämät does not have a clear, widely accepted grammatical role in modern Finnish and is typically considered nonstandard, dialectal, or archaic.
In practice, if you encounter a phrase that looks like käyttämät, it is more likely a misspelling
Grammatically, Finnish participles are built from the verb stem and a set of published endings to mark
See also: käyttää, käytetty, käytetyt, käyttämättömyys, kielioppi.