The mounting of safety valves is not required for VBAT series air tanks because they are not required for Class 2 pressure vessels in Japan.
If a safety valve needs to be mounted, it can also be mounted by branching it with a cheese, etc., from the OUT port.

SMC's VP300/500/700 series solenoid valve, offers high flow capacity and reduced power consumption (1.55W standard, 0.55W with power saving circuit).  The series may be used as either a selector valve, or a divider valve.  It is vacuum applicable up to –101.2kPa.  Series VP3145/3165/3185 is a large size, 3 port solenoid valve with a rubber seal.  It is possible to use the series in vacuum