TD-4, TD-4S, TD-4SX: Where is the Serial Number?
The serial number for the TD-4 is located on the underside (bottom panel) of the TD-4 module. It contains 2 letters followed by 5 numbers- (XY-12345).
If you are sending in your warranty registration or rebate info, use the TD-4's serial number only. This represents the entire kit.
Note: It is not necessary to list individual serial numbers for each pad or cymbal.