In a word - you must have one! Go out and buy one if you don't already own one - it's usefulness goes way beyond just cooking with chocolate! These work by reacting instantly to changes in temperature - you just dip, read - continue. Essential.
Can any good brand of chocolate be used for dipping strawberries and still set up hard when cool? If not, can anything be done to it or added to the melted chocolate to ensure it will set up hard to the touch?