Extended Validation (EV) certificates were designed to strengthen e-commerce security and combat phishing attacks. The green address bar provides highly visual assurance to visitors that the site is verified and secured and aids customer conversion. Usually priced at $449, Comodo SSL customers receive a free upgrade to EV for the first year of their certificate at no extra charge (note - upgrade does not apply to wildcard certificates)

EV upgrades are for the first year of your certificate term and are limited to one upgrade per-domain.