.090 There is 1 product.

A folk guitar string purchased individually with a tension of 0.90 probably refers to the measurement of string tension in kilograms-force (kgf) required to produce the fundamental note of the string when tuned to the specified pitch.

In the context of acoustic guitar strings, a tension of 0.90 kgf generally corresponds to a medium gauge string, usually the D (D) or A (A) string in a standard set of strings.

However, it is important to note that different brands and string manufacturers may use different systems of measurement to describe the tension of their strings. Therefore, it is important to refer to the manufacturer's exact specifications to ensure that you are purchasing the correct guitar string for your instrument.