The hammered dulcimer derives its name from the small mallets that players use to strike the strings, called hammers. Hammers are usually made of wood (most likely hard woods such as maple, cherry, padauk, oak, walnut, or any other hard wood), but can also be made from any material, including metal and plastic. In the Western hemisphere, hammers are usually stiff, but in Asia, flexible hammers are often used. The head of the hammer can be left bare for a sharp attack sound, or can be covered with adhesive tape, leather, or fabric for a softer sound. Two-sided hammers are also available. The heads of two sided hammers are usually oval or round. Most of the time, one side is left as bare wood while the other side may be covered in leather or a softer material such as piano felt.
Several traditional players have used hammers that differ substantially from those in common use today. Paul Van Arsdale (b. 1920), a player from upstate New York, uses flexible hammers made from hacksaw blades, with leather-covered wooden blocks attached to the ends (these are modeled after the hammers used by his grandfather, Jesse Martin). The Irish player John Rea (1915–1983) used hammers made of thick steel wire, wound with wool. He made these himself from old bicycle spokes. Billy Bennington (1900–1986), a player from Norfolk county in England, used cane hammers bound with wool.
 Four-hammer dulcimer
The four-hammer dulcimer is a standard hammered dulcimer instrument played with special hammers and technique. This innovation premiered in the early 1990s.
The first record of a four-hammer dulcimer is Glenn McClure’s variation of the Burton grip. McClure’s hammers are wooden dowels with teardrop-shaped heads. One hammer is held between the pad of the thumb and the midsection of the forefinger. The handle of the second hammer is a 2.5 cm square pad, which is gripped in the middle and ring fingers. Swiss player Barbara Schirmer is another practitioner of the four-hammer technique.
Another hammer design is two standard flat-handled hammers riveted together about 4 cm from the base so they can pivot. As of yet, no technique has been developed for these hammers.
The hammered dulcimer was extensively used during the Middle Ages in England, France, Italy, Germany, Holland and Spain. Although it had a distinctive name in each country, it was everywhere regarded as a kind of psalterium. The importance of the method of setting the strings in vibration by means of hammers, and its bearing on the acoustics of the instrument, were recognized only when the invention of the pianoforte had become a matter of history. It was then perceived that the psalterium in which the strings were plucked, and the dulcimer in which they were struck, when provided with keyboards, gave rise to two distinct families of instruments, differing essentially in tone quality, in technique and in capabilities: the evolution of the psalterium stopped at the harpsichord, that of the dulcimer gave us the pianoforte.