There are three categories of models depending on method they made.
“Bent” vargans: the frame is prepared by bending a metal wire. These are ”shaman’s” models adjusted with timbre of human voice specially. These models are popular for Tuvinian troat-singing. This singing uses special parts of vocal cords which are never used for everyday talking.
“Forged” instruments. The frame prepared by handmade forging. This technology changes physical properties of metal making it plastic. Instruments obtain powerful three-dimensional timbre as a result. “Forged” instruments are for professional musical playing or some shaman practice.
“Hexahedral” vargans with elements of forging. Instruments have hexahedral frame. Bright, powerful sounds, intermediate between “forged” and “bent”.
There are a lot of ethnic varieties of vargans (Jew’s harps) made by folk craftsmen. I make instruments with Slavic roots. Kazah vargan (it is called khomuz there) sounds entirely differently, because of different roots and technology.
