Guzheng is normally played with plectra. Striking the string with a plectrum instead of the natural nail gives a clearer attack and more consistent tone, and protects the nail from wear.
Common materials include horn, tortoiseshell substitutes and various polymers. Hardness and elasticity differ, and so does tone; choose according to your playing habits and repertoire.
Thickness and curvature also affect feel. Thicker plectra give more volume and projection; thinner ones make it easier to produce a light, delicate sound. Beginners are usually safest starting with a medium thickness.
Tape the plectrum to the outer side of the fingertip, tight enough that it does not shift while playing but not so tight that it restricts circulation. Tape wound too tightly makes the finger numb; too loose and the plectrum slides during rapid passages.
Plectra and tape are consumables. Replace them when they crack or show obvious wear, so they do not break mid-performance and scratch the strings or soundboard.