For example, instruments like thermometers and barometers are measuring devices.

Literal

For-example, thermometer [or-や] barometer [of-など] [of-の] measuring-device [topic-は] instruments [copula-です].

や~など combines the non-exhaustive list marker や with the open-ended など ('and such') — 'things like A, B, and others.' 計器 ('measuring device') is a technical noun. The whole sentence is a classifying definition.