Connector butt 12-10 AWG 2 crimp (3 mm2 - 5 mm2) 25 pc

Nylon Butt Connector Double Crimp, 12-10, 25pc
210163
Ancor's Marine Grade terminals differ from automotive terminals by being designed for the harsh marine environment. 
Nylon insulators are easy to crimp and will not split. Barrels are designed to tightly grip the wire with the least effort. 
Tinned copper gives the least electrical resistance but the most corrosion protection.

Nylon insulated with insulation grip
Funnel entry
UL 486C
Selecting the proper wire terminal for marine applications is important