If you are looking at a plug, locate the numbers or NEMA term on the base of the plug to help figure out what you need to connect to it. Then look at the outlet or power source to find the NEMA term you are trying to power from. You may have read a NEMA configuration or code on an adapter that includes a P or an R after a set of numbers and letters (Example: ASL1420R). NEMA codes are the standard industry electrical connection language used in the U.S. Some people get confused by the P and the R or by the relationship between the two of them. Read more about this topic in our blog post: Relationship Between the Plug and Receptacle (P and R).