The Model ES-660-B is our new generation hatch designed with precision-manufactured internal components, a round base and cover, and is intended for use in applications where ultra-tight sealing is required such as sour crude/gas or where strict environmental emissions standards are enforced. The Model ES-660-B is provided with a bleeder attachment, making it possible to relieve tank pressure before opening the hatch. The bleeder prevents a spray from discharging when the hatch cover is raised. The Model ES-660-LB is our new generation hatch designed with precision-manufactured internal components, a long base and cover with an inclining base, and is intended for use in applications where ultra-tight sealing is required such as sour crude/gas or where strict environmental emissions standards are enforced. The Model ES-660-LB is provided with a bleeder attachment, making it possible to relieve tank pressure before opening the hatch. The bleeder prevents a spray from discharging when the hatch cover is raised.