'4-pole male chassis connector, black metal housing, ¼'' flat tabs, countersunk through holes. This connector fully complies with the IEC 62368-1 device standard, due to its component certification to IEC 61984. speakON's STXX series was specially designed for heavy-duty speaker-amplifier applications, such as professional touring. The extremely strong and durable STXX series features an all-metal housing.'