dual variable domain immunoglobulin 

Creative Biolabs offers clients a novel bispecific antibody (BsAb) format, the dual variable domain IgG (DVD-IgG), for many diverse studies in antibody engineering. We aim to provide the reliable, efficient services to meet our customer’s individual requirements.
https://www.creativebiolabs.net/dual-variable-domain-igg-dvd-igg.htm