Non-Insulated Terminals & Connectors: Non-Insulated Butt Connectors (Seamless): The Seamless feature is only available for butt connectors or butt splices. The barrel is created to form one seamless point of metal. This eliminates the problem of the barrel opening. May be used with solid or stranded wire. Non-Insulated Terminals & Connectors are made of 100% pure copper for maximum conductivity with the addition of tin plating for marine applications. Where applicable, serrated barrel offers increased pullout strength of hard-to-crimp solid or stranded wire. Can be crimped or soldered. 600V rating.