Greenlee SDMM-1 Instruction Manual page 6

Identification
1. Removable Test Probe
2. Fixed Test Probe
3. Display
4. Feature Buttons
5. Warning Light
1
6
Negative (–), common probe or ground
Positive (+) probe
3-3/4-digit LCD (3199 maximum display) and bar graph
See explanations under Using the Features
Illuminates when voltage exceeds 50 V
2
3
5
4