The UR2 Connector accepts any two or three solid copper conductor combinations of 19-26 AWG (0.9mm - 0.4 mm) air core or filled cable with a maximum insulation O.D. of .082" (2.08 mm). The wires joined can be of different wire gauges.
Its three ports accept two or three conductors for butt splicing. And like most Scotchlok Connectors, the UR2 is filled with a sealant to provide moisture resistance.
The E9Y step plier tool is the approved tool for the UY2 and UR2 connectors. Also availabled is the E-9BM which has parallel closing action with adjustable jaws, and features high mechanical advantage.