Features: Application 800-643 Line Splice fits for 5/16 in. Aluminum Lines, works for A/C, coolant, heater, oil, P/S return, and trans line repairs. Material The nuts are made of premium aluminum with excellent corrosion and rust resistance. The expanded seal sleeves made of rubber provide more sealing area. The tension rings are made of copper, having a great vibration-leak resistance. Function This kit has a high performance against corrosion and rust, effectively rebuild air conditioning to original operating temperatures and prevent future breakdowns. Inatallation .