Planning Poker is an agile estimating and planning technique. To start a poker planning session, the product owner reads an agile user story or describes a feature to the estimators.
Each estimator is holding a deck of Planning Poker cards with values like 0, 1, 2, 3, 5, 8, 13, 20, 40 and 100. Attached you can freely download printable Scrum poker planning cards.