F(ab')2

F(ab')2 (dimer of an antigen-binding fragment) is IgG minus Fc (the constant/crystalline/complement-fixing fragment). It has 2 antigen-binding paratopes.

Spacefilling model of F(ab')2 fragment.
   

Spacefilling:
    Heavy Chain,
Heavy Chain.
    Light Chain,
Light Chain.

Cartoon,
    Disulfide bonds.

Backbone.
    Hide backbone.

Zoom to inter-chain disulfide bonds.