If you're trying to RMA a Crucial SSD with model number
CT960M500SSD1 (M500 2.5" 960GB SSD), then the material number is
The first step to starting the RMA with Crucial is to give them the "Material Number" for the SSD or memory. However my SSD had no material number on it - it has every other number you'd want to know: model, part, serial, "WWN", "L/N", but no "material number". It seems that Crucial wants you to call customer service for troubleshooting assistance before you can start an RMA - if you're an IT professional that might be a waste of time. I got the material number by wading through Crucial customer service. I hope this helps someone.