Rocket is a peppery salad leaf plant known also as rucola, rughetta, arugula and roquette. The size of the leaf varies, but the more mature and the bigger the leaves are, the better and stronger the taste. Rucola di Capri is a wild rocket with very small leaves, more like a herb than a salad plant.
Use as soon as possible, washing it well and discarding yellowed leaves and tough stems.