According to its form or physical appearance, there are two kinds of kacapis:
Kacapi siter is a plan-parallel resonance box. Similar to kacapi parahu, its hole is located at the bottom. The upper and bottom sides of it form an almost-trapesium shape.
For both kinds of kacapi, each string is affixed to a small screw or peg on the top right hand side of the box. They can be tuned in different system: pelog, sorog/madenda, or salendro.
Nowadays, the resonance box of kacapi is made by glueing six wood-plates side by side.Form
Kacapi Parahu is a resonance box with uncovered underside to allow the sound out. The sides of this kind of kacapi is taper inward from top to bottom, which gives the instrument a boat-like shape. In ancient time, it was made directly from solid wood by perforating it.