15A Half Controlled Thyristor Bridge.
Field Bridge for Parker SSD - DC thyristor Drive. (10A field option)
SSD Part number is CF057273U016 (CFO57273U016)
Manufacturers part number is IXYS VHF 15-16io5 or WES303 (VHF15-16io5)
SSD are a division of Parker Hannifin, previously known as SSD Drives, Eurotherm Drives and Shackleton System Drives.