CURT Automotive Primary Wire, Red 500' Spool Model 57037CURT Automotive Primary Wire, Red 500' Spool Model 57037 CURT automotive primary wire is engineered for dependable performance, boasting a 12 gauge wire thickness to ensure reliable connectivity in trailer setups. With the standard red trailer wiring color, it simplifies rewiring tasks. Rated for 60 volts, it's perfect for both trailer rewiring and automotive electrical repair applications. Its robust design withstands temperatures from 40F to 176F,