All of the feet on the bottom (which are required for leveling). The accuracy certification is long overdue, but its accuracy was verified by weighing several objects with another identical scale. They both weighed the objects within .1 gram of each other. (The other scale is not available because it is missing the plastic discs that support the tray.)
Sartorius BL1500 Portable Top-Loading Precision Balance Scale 0-1500 mg
$49.95
Brand
Sartorius
Model
BL1500
MPN
BL1500
Country/Region of Manufacture
United States
Scale/Balance Type
Top Loading Balance
condition
Used
This scale works great with a 9-volt battery. The bottom label says that it will work with 11 to 21 volts, and it was tested with power adapters ranging from 9 volts to 19.5 volts with no response. It's possible that it didn't work because Sartorius has a unique power connector.