Documentation states 0,8-2,0mm wire size, but I didn't get a satisfactory contact using 1,5mm diameter wire. Ended up adding a dab of solder on the wire end just in case, which kind of defeats the purpose. The plating on these is nice, so soldering was easy. Fits securely on Neutrik NA3CMPA-1 terminals.
I would recommend these for installment use with other Neutrik products as these seem to fit well. Material is kind of soft, so wouldn't expect these to survive rough use. Prepare to crimp&solder if using <2,0mm wire.