Abstract: This invention provides a crime preventing device capable of repelling a criminal and blocking an escape. A remote-controllable liquid sprayer 3 is incorporated in the inside 2 of a counter 1 and a nozzle 4 of the liquid sprayer 3 is disposed on the bottom of a front face 5 of the counter 1, the liquid sprayer 3 being charged with spraying liquid containing odor component. By spraying the odor component over the foot portion of a criminal, the criminal is repelled by that odor so as to block execution of a crime and the odor sticks to the trousers or shoes which the criminal cannot throw away easily during an escape securely.

Abstract: A polycrystalline ferrite containing Na, Zr and Ca in amounts of 0.01 to 0.5% by weight, 0.005 to 0.5% by weight and 0.01 to 0.5% by weight respectively, in Mn-Zn or Ni-Zn ferrite to thereby enhance the toughness of said ferrite. Said ferrite is suited for a magnetic head with improved mechanical strength and excellent fine workability.