Hello, You can purchase a good dholak from music instruments shop. you must ask the wood type as it is of made. some dholak are made of mango tree and some likely tree that destroyes by insects soon. Sheesham and Katahal wood and likely trees wood which is costly and having strength. it is costly dholak and it makes better trebal and bass sound with it. One must see the dholak from inside as now a days dholaks are of nut bolt. dholak from inside should be one piece and not any cracks should be found which is filled by dholak seller with some technique. It comes out after using dholak for few months. Even from outer side you must see any crack is filled ? you may find it easily by looking and making palm on surface of the dholak. If all is well you can purchase one. normally treble side is smaller than Bass side. Treble side may be 5 and 1/2 inch or near about. and bass side may be 10 inches or near about. that sounds a dholak very nice. both side khaal should also be checked for any cut or small holes of ants or it is uneven in thickness. sometime seller sells a dholak which is uneven in thickness of is khaal or side. then when you beat the dholak it tears from the point from where it is thin. Dholak should be heavy in weight. So all these point should be kept in mind while purchasing a dholak.