What face parts are included with this model?

Three face parts are included: Smiling/Looking Right, Troubled/Looking Left, and Glaring/Looking Right.

Is this Hresvelgr Bikini Armor Version model pre-painted and pre-assembled?

Yes. It is described as a pre-painted and pre-assembled plastic model, and the paint job is based on Kotobukiya's plastic model paint master.

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Kotobukiya Frame Arms Girl - P3 Hresvelgr Bikini Armor Version Model - FG175

A pre-painted and pre-assembled plastic model.
The paint job is based on Kotobukiya's plastic model paint master.
For the P3 version, all of Hresvelgr Bikini Armor Version's markings are recreated with tampography.
The flexibility of the model's hip joints and thighs has been drastically improved for better action poses.
Three types of face parts are included (Smiling/Looking Right, Troubled/Looking Left, and Glaring/Looking Right).
The pop-out shoulder joints and the flexible upper arm parts allow for a wide range of movement.
The connection shaft for the thighs is a sliding joint, allowing for a wide range of movement.
The hand parts are attached with a ball joint, allowing for a wide range of expressive poses.
The model kit includes five sets of PVC hand parts. The hand parts, including the joints, are compatible with the other hand parts within the Frame Arms Girl series.
The 3mm connection points on the arms and legs are compatible with equipment from the M.S.G and Frame Arms series.