The magician use a standard craft knife to cut rope, open an envelope, etc during their act. Looking somewhat maniacal they then turn the knife on themselves slicing right into their own finger.
The classic knife through arm made somewhat smaller and more portable. Looks very good close up and can be used as a real knife, just requires the addition of some acting and if you wish a little fake blood.
Warning: These props are produced from real craft knifes and the knife remains sharp around the gimmick. As with all knifes care must be taken with the handling. This item is not for sale to those under 18 years of age.