Perpetual Timepiece is a uncommon Artifact card from Kaladesh (KLD), collector number 227. Current market price: $0.31 (foil $5.95), TCGplayer market prices via Scryfall.
{T}: Mill two cards. (Put the top two cards of your library into your graveyard.) {2}, Exile this artifact: Shuffle any number of target cards from your graveyard into your library.