BOX COUPLERS are predominately utilized in laboratory applications. 

ESI-110
One Stub Box Coupler - BJ77 (3 lug) Connector
ESI-110 datasheet
ESI-111
One Stub Box Coupler - internally terminated
ESI-111 datasheet
ESI-120
One Stub Box Coupler - BJ377 Threaded Connector
ESI-120 datasheet
ESI-130
One Stub Box Coupler - BJ157 Connector
ESI-130 datasheet
ESI-140
One Stub Box Coupler - BJ3157 Connector
ESI-140 datasheet
ESI-150
One Stub Box Coupler - BJ77FL (4 lug) Connector
ESI-150 datasheet