Pack of 6 fork crimp terminals, which fit the connectors on the Morningstar SunSaver range of solar regulators. These aren't essential - connections can be made to the terminals with bare wires - but they certainly make a neater job!
These terminals are compatible with both 2.5sqmm and 4sqmm general purpose cable.
For best results, use a proper crimping tool to apply, but a pair of pliers or a vice will produce a reasonable result.