Ford 6.8 serpentine belt

Call Dodge Tech support - or any Dodge Service department with your VIN. They should be able to get the correct part number for you. Here are two numbers I found no idea if they are 24/7 or workdays only.
Dodge (800-423-6343) 800-4ADodge
RAM (866-726-4636) 866-RAM-INFO

For future, buy 2! keep a spare. We have a fresh spare with us at all times. Cheap insurance - Freightliner recommends that for their chassis.