This is Vishnu and his consorts Sridevi and Bhudevi. Vishnu is towering over his consorts, and his height is three times that of his consorts. Quite a forceful and visual way showing position and power.
Vishnu is holding Chakra, Gada, Shankha and Padma (Discuss, Mace, Conch shell and Lotus) in his hands. Clockwise starting with his lower right hand. Vishnu and his consorts are standing on inverted lotus which in turn is supported by Triratha type Bhadrapeetha.
The prabhavali is quite stylized and topped by Kalasa, an auspicious water pot. On top of prabhavali’s verticals are two four-armed figures. Quite possibly they are Siva and Brahma, worn and small for positive identification. Vishnu’s backdrop is a halo designed like a lotus.
This Vigraha is possibly from Gujarat (Western India for sure). The material, relative sizes of Vishnu and his consorts (In South India Vigrahas the consorts are larger in size), the stubs connecting the deities to the prabhavali, design of Vishnu’s crown (the side protuberances) are some of the features that lead to the geographic attribution. The Vigraha is about 16.5 cm in height. This vigraha may be dated to the 16th-17th century.
Reference: Heritage of Metallic Art of Gujarat (1995) by Swarnakamal. Published by Department of Museum, Gujarat.
Below is a composite image of some of the other Vishnu triads in my collection.