BOX COUPLERS are predominately utilized in laboratory applications. 

ESI-410
Four Stub Box Coupler - BJ77 (3 lug) Connector
ESI-410
ESI-4210 / ESI-4310
Four Stub Box Coupler - internally terminated
ESI-4210 / ESI-4310
ESI-410D
Four Stub Box Coupler - BJ77 Connector - Dual Bus
ESI-410D
ESI-4210D / ESI-4310D
Other internally terminated 4 stub couplers
ESI-4210D / ESI-4310D