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. Features: Nylon insulated with insulation gripDouble crimp, funnel entryUL 486CWARNING: This product can expose you to chemicals including di(2-ethylhexyl)phthalate (dehp) which is known to the State of California to cause cancer, birth defects or other reproductive harm.