A cassette for storage of at least one medical instrument, the cassette including at least one spring sheet, the spring sheet including at least one holding means for retaining the medical instrument therein, the holding means including an aperture forming a passage through the spring sheet for receiving the medical instrument and at least one spring element provided adjacent to the passage for exerting a biasing spring force to retain the medical instrument within the passage, and wherein the spring sheet, including the holding means, is made of a metal or a metal alloy.