Quality, Reponsive Customer Service. Raypak 010366F Tube Bundle Copper 336 & 337 Polymer Cupro Nickel for Heating. Item has been opened and is in the original retail packaging. This item shows signs of limited use, but remains in great condition. Cosmetic flaws may include minor scratches and/or scuffs. Item has been professionally tested and inspected to ensure complete functionality. Tube Bundle Cupro Nickel Features – Tube Bundle Copper – Model – P-R337A, P-R336A. Tube Bundle Cupro Nickel Features. Model – P-R337A, P-R336A. Item model number: 010366F.