Framed by prabhavali and with serpent hood, this four armed Durga is sitting in lalitasana/maharaja lalitasana pose. Durga’s rear hands are holding wheel and conch, typically the attributes of Vishnu. Her right front hand is in Vitarka (teaching) mudra and she is holding a bowl in her left hand. There are three spherical objects in front her on the pedestal. In the absence of these spherical objects she could be identified as Vaishnavi, depending where she is coming from. In this form she is sometimes call Vishnu Durga.
The serpent’s body runs down her back, rather than be a part of prabhavali as commonly seen. There one other bronze in my collection where this is the case.
Shrines of Durga may be independent or the subsidiary in temples dedicated to Shiva and Vishnu. But Durga is worshipped on her own, as the concept of Durga involves her superiority over all male divinities.
This is about 9 cm in height and is made of brass. This icon is likely to have come from North Karnataka or Maharashtra (Western Deccan region). There is significant ritual related wear and still has power (kumkum) used in puja. Going by the wear, this may be from the 19th century or slightly earlier.