Hollow cast in one piece.
The bottom of the pedestal is not sealed. 
 
Vajrasattva (Tib. rDo rje sems dpa’) is seated in the diamond attitude (vajraparyankasana) on a double lotus standing upon a rectangular pedestal. The right hand holds a five-pronged diamond sceptre (vajra) in front of the chest and the left hand resting on the left leg holds a prayer-bell (ghanta). Vajrasattva is clad with a cloth (dhoti) tied around his waist with a belt and carries a ribbon-like scarf over the shoulders with the swirling ends pointing upwards. He wears jewelled ornaments, namely a small three-pointed crown in front of the knot of hair (jatamukuta), a pair of circular earrings, a necklace, the “investiture with sacred thread” (upavita), and braclets at the wrists. The image is encircled by a broad aureole (prabhamandala) decorated with rays, and the head set off against a pointed aureole. 

Vajrasattva
Tibetan Vajrasattva holds the vajra in his right hand and a bell in his left hand.
Vajrasattva (Dorje Sempa, Tibetan, Kongosatta, Japanese), (Jingang Satuo, Chinese), or Diamond Mind (see Vajra), is a buddha figure in the Mahayana and Vajrayana buddhist traditions. In Japanese Shingon buddhism, Vajrasattva is the name by which the bodhisattva Samantabhadra is referred after the practioner has received initiation into the “esoteric” or Vajrayana practices. In the initiation practices of Vajrayana Buddhism, many Buddhist figures assume different identities to signify their new form after initiation, complementary to the old form before initiation. In lineages of initiation such as Shingon Buddhism, Vajrasattva is also seen as the initiator of that lineage. Traditionally, Nagarjuna was said to have met Vajrasattva in a tower in South India, and was taught tantra by Vajrasattva, thus transmitting the esoteric teachings to historical figures.
 
Shingon Buddhism
Vajrasattva is an important figure in two esoteric Buddhist sutras, the Mahavairocana Sutra and the Vajrasekhara Sutra. In both sutras, Vajrasattva plays the role of the student, who learns the Dharma from Mahavairocana Buddha, and is taught the esoteric rituals to help actualize the Dharma. In Shingon Buddhist rituals for initiation, the initiate re-enacts the role of Vajrasattva and recites mantra and dialogue from the tantric texts, known as sutras in Shingon buddhism. The teacher enacts the role of Mahavairocana Buddha bestowing wisdom.
In Vajrayana Buddhist practice, Vajrasattva is used in the Ngondro, or preliminary practices, in order to "purify" the mind's defilements.
 
Tibetan Buddhism
In Tibetan Buddhism the Vajrasattva root tantra is Dorje Gyan, or “Vajra Ornament”. Vajrasattva practices are common to all of the four schools of Tibetan Buddhism and are used both to purify obscurations so that the Vajrayana student can progress beyond Ngondro practices to the various yoga practices of tantra and also to purify any broken samaya vows after initiation. As such, Vajrasattva practice is an essential element of Tibetan Buddhist practice.

de Mallmann, Marie-Thérèse, 1975. Introduction à l'iconographie du tântrisme bouddhique. Paris: Adrien Mainsonneuve (Jean Maisonneuve successeur (1970). Pp. 396, 406: Vajrasattva as Bodhisattva - References to the iconography of Vajrasattva

Sèngué, Tcheuky, 2002. Petite Encyclopédie des Divinités et symboles du Bouddhisme Tibétain. Editions Claire Lumiere . Pp. 108-109

von Schroeder, Ulrich, 1981. Indo-Tibetan Bronzes. Hong Kong: Visual Dharma Publications, Ltd.. Pp. 152–53, pl. 28D: Vajrasattva. Western Himalaya, 950–1050 AD