Don't know what LED is there (3 mm?) near output conector but through-hole optocoupler (817) have about 4.6 mm wide case, so low voltage connector can be about 4 mm (3.96 mm) or 5 mm (5.08 mm). And high voltage connector I think has the same pitch (but 3 pin).
A3960H (=VH) type (or NX5080)?