Provided is a multifunctional hand warmer including a base, a net cover, a heating component and a heat transfer plate; the net cover is on the base, and the heat transfer plate is on the top of the net cover; a cavity is defined between the net cover, the base and the heat transfer plate; the heating component is in the cavity.

A heat exchanger is disclosed. The heat exchanger includes a protective device, mutually parallel tubes through which a first fluid circulates, and perpendicular fins connecting two successive flat tubes, a second fluid circulating between said flat tubes by passing through said fins, the protective device being apertured so as to allow the circulation of the second fluid through the fins. The protective device includes fixing spikes which are inserted forcibly between the fins.

The present invention relates to a heat exchanger (20) comprising a protective device (1), mutually parallel tubes (22) through which a first fluid circulates, and perpendicular fins (26) connecting two successive flat tubes (22), a second fluid circulating between said flat tubes (22) by passing through said fins (26), said protective device (1) being apertured so as to allow the circulation of the second fluid through the fins (26), said protective device (1) comprising fixing spikes (7) which are inserted forcibly between the fins (26).