Polite conjunction used to connect contrasting statements. Often appears at the start of a sentence or after a polite clause. Equivalent to だが in plain speech.
He is kind, but a bit forgetful.
この部屋は広いですが、家賃が高いです。
This room is spacious, but the rent is expensive.
だが is the plain, casual counterpart of ですが, which is used in polite speech or writing.
Polite form of the copula だ (です) combined with the conjunctive particle が.