This is a brass long length Diya/Dipak/Lamp. It has a semi-ball-shaped space which is used to lit the lamp. It is used in the ritual of south Indian peoples.
It is known as Saal deep, Saldeep, Shaaldeep. It comes in various numbers to lit the lamp e.g. 2,3,5,7,9,11,21 and 27.
To lit the lamp in sequence made of brass.