Abstract: A timer comprising a lamination containing a piece of porous wick material 1, and a reservoir of liquid 6, said liquid 6 and/or said porous wick 1 being such that when the reservoir is opened and the liquid 6 released it soaks into the porous wick 1 to thereby create a visible trace of the liquid on or in the porous wick; a face part 2 of the lamination being transparent such that said visible trace can be seen; said wick material 1 having imposed thereon or positioned adjacent thereto a series of markings which cover the time range over which the timer is to be used. The invention also provides a method of manufacturing the timer.