This is a Chinese aromatic ground spice mixture which has no absolute recipe but which usually includes cloves, cinnamon, fennel seeds, schezuan pepper and star anise. It may also contain powdered ginger, aniseed and nutmeg or mace.
It is most frequently used to flavour meats prior to roasting. Bought in powdered form, its volatile oils rapidly dissipate, leaving you with only a hint of what might have been. It is therefore preferable to make it yourself from roasted whole seeds, grinding them only minutes before use.