INSERTA^® UNIFIED CODE U61 4-Bolt Modular Connectors are used in integrated hydraulic systems in place of welded and threaded pipe fittings. The UNIFIED CODE U61 4-Bolt pattern is the same as the CODE 61 but their ports and connecting flange footprints are significantly smaller. Design-A and Design-B Inserta^® Modular connector (IEL) elbows, (ITR) tee runs, (ITB) tee branch, (ICX) crosses, (IPS) port spacer and (IPN) port connector (design-C only) are held in place by bolts (Socket Head Cap Screws). Socket Head Cap Screw Fasteners are used with the INSERTA UNIFIED CODE U61 4-Bolt Modular Connectors and the ADAFLANGE UNIFIED CODE U61 4-Bolt Adapters. The INSERTA^® UNIFIED CODE U61 4-Bolt Modular Connector, should be considered whenever the features of the larger CODE 61 and CODE 62 Modular Connectors are not required.