What the number identifies
A LOT number points to a listing in the auction system. It should not be confused with the 17-character VIN, which identifies the physical vehicle, or an item value that helps organize sale order.
How to copy it safely
Copy the number from the official vehicle page rather than typing it from memory. After searching, confirm the vehicle description and VIN because a single wrong digit can lead to a different result or no match.
How VINsniper uses it
VINsniper uses the LOT to locate available sale and queue information, then associates the selected notification threshold with your account. The LOT is used for monitoring, not for placing a bid.