The right to conduct a specified activity at a specific repeated time, usually daily. Such rights frequently become legally vested by passage of time or by contract and since they have gained many of the attributes of intellectual property are known as quasi-intellectual property. Most slots arise in the transportation sector, and include airport takeoff slots, ferry terminal slots and railway line and platform slots. A major pitfall of these rights is that they are not universally recognized to be property which can create issues with their sale or legal transfer.