A Mezrāb or zakhmeh is a plectrum

Plectrum

A plectrum is a small flat tool used to pluck or strum a stringed instrument. For hand-held instruments such as guitars and mandolins, the plectrum is often called a pick, and is a separate tool held in the player's hand...

 which is used for several Iranian and Indian string instrument

String instrument

A string instrument is a musical instrument that produces sound by means of vibrating strings. In the Hornbostel-Sachs scheme of musical instrument classification, used in organology, they are called chordophones...

s.

For Sitar

Sitar

The 'Tablaman' is a plucked stringed instrument predominantly used in Hindustani classical music, where it has been ubiquitous since the Middle Ages...

, a mezrab is worn on the finger

Finger

A finger is a limb of the human body and a type of digit, an organ of manipulation and sensation found in the hands of humans and other primates....

 of a Sitar

Sitar

The 'Tablaman' is a plucked stringed instrument predominantly used in Hindustani classical music, where it has been ubiquitous since the Middle Ages...

 player. It is a plectrum

Plectrum

A plectrum is a small flat tool used to pluck or strum a stringed instrument. For hand-held instruments such as guitars and mandolins, the plectrum is often called a pick, and is a separate tool held in the player's hand...

 made by hand from a continuous strand of iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 used to strike the strings of the sitar. Although it is generally worn on the index finger

Index finger

The index finger, , is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger...

, a second mezrab is sometimes worn on the middle

Middle finger

The middle finger or long finger is the third digit of the human hand, located between the index finger and the ring finger. It is usually the longest finger...

 or little finger. The mezrab fits tightly on the end of the finger so that it does not move while playing, intended to be projected roughly 1/4 inch from the end of the finger.

Mezrab is also the name for the lightweight wooden hammer used to play the Persian santur

Santur

The santur is a Persian hammered dulcimerIt is a trapezoid-shaped box often made of walnut or different exotic woods. The Persian classical santur has 72 strings. The name santur was first referenced in ancient Persian poetry...

.

Different strokes used

There are four different Bols (strokes) used when playing sitar

Sitar

The 'Tablaman' is a plucked stringed instrument predominantly used in Hindustani classical music, where it has been ubiquitous since the Middle Ages...

: Da, Ra, Dir and Dra.

• Da Bol - When the stroke is from outward to inward on the first string.
• Ra Bol - When the stroke is from inward to outward on the first string.
• Dir Bol - When the first string is stroked rapidly from both sides. (similar to tremolo picking
  Tremolo picking
  Tremolo picking, also known as alternate picking or double picking, describes the musical technique of picking on a guitar or other string instrument in which a single note is played repeatedly in quick succession. It can be achieved either with the fingers or with a pick...
  
  on guitar)
• Dra Bol - when the first string is stroked from inward and then immediately outward very fast, giving the outward stroke more power/emphasis than inward stroke.