This is the RC Electronics Watts Up Watt Meter with Blue Case.

FEATURES: Works with any electric airplane, helicopter, car or boat model
High resolution on all measurement ranges to accurately check battery
battery pack cell balance and measure single cell packs
Connects like jumper cables and troubleshoots poor performance,
crashes, charging problems, battery capacity, ruined batteries,
erratic receiver and servo operation and many other common electric
model problems
Sets cutoff currents and voltages, compares components and detects
wear prior to component's failure
Measures eight essential electrical values;
Captures Peak Amps, Peak Watts and Minimum Volts events as short as
a fraction of a second
Current: 0-100A Peak, 50A Continuous, 0.01A Resolution
Charge: 0-65535mAh, 1mAh resolution
Power: 0-6500 Watts, 0.1W Resolution
Voltage: 4-60 Volts, 0.01 Resolution (0 V min. using auxiliary
receiver battery
Energy: 0-6500 Watt Hours, 0.1WH resolution
Powered by circuit-no battery to change
16 character, 2 row LCD display
8 MIPS microprocessor and DSP firmware for highest performance
One year warranty

INCLUDES: RC Electronics Watts Up Watt Meter, four 3.8" (96mm) length 14 gauge
stranded silicone source and load wires without connectors,
instructions

REQUIRES: Connectors depending on type of battery

SPECS: Length: 2.8" (71mm)
Width: 1.7" (43mm)
Height: 0.83" (21mm)
Weight: 2.3oz (65g)