Here's one source. I'm going crazy at this site! Buying since August. Happy customer.
Edit: Seems I bought one
Blue. As described. Works well at 4vdc.
Do not measure the supply voltage running the module!
Do not try to measure - voltage (with respect to the test leads) you will just see 0.00 volts.
**broken link removed**
Description :
MINI DC 0-32V 3-Digital LED Display Voltmeter
Features:
Low start-up voltage, the red minimum 2.5V, green minimum 2.7V, blue minimum 3.0V.
Supply voltage is lower than 3.5V, the only decrease in brightness, but does not affect measurement accuracy.
Has reverse polarity protection, reverse does not burn.
Specifications :
Measuring range : DC 0V--32V
Input range : DC 2.5V-32V(Max Input : DC 32V. The device can be damaged if input is over 32V)
Red DC2.50-32.0V, Green DC2.70-32.0V, Blue DC3.00-30.0V
Display : Three 0.36 "digital tube
Measurement accuracy : 0.1%
Refresh rate : about 300mS / times
Input impedance : About 100K
Operating Current : Red <23mA, Green <18mA, Blue <13mA
Dimensions : 33mm*15mm*10mm
pitch of holes : 28mm
aperture size : 2.8mm
Operation Temp : -10℃-+65℃
Display Color : Red, Blue, Green
Lead Length : 15cm
Wiring :
Red : power supply +
Black : power supply -, measure -
white : measure +
Package included :
1 x 3-Digital LED Display Voltmeter