Step-up step-down 3.3V voltage regulator (buck-boost).

These are great modules to regulate 3.3V projects. They are different from the normal 3.3V regulators as they will boost voltages below as well as take voltages down to 3.3V if higher.

Step-up step-down 3.3V voltage regulator (buck-boost) description:
Low Noise, Regulated Charge Pump DC/DC Converter
2 in 1 DC-DC Step-Down & Step-Up Converter module
Fixed 3.3V+-4% Output
Voltage Input Range: 1.8~5V
Long time maximum output current 100mA
Short time maximum output current 150mA
working frequency 1.2MHz.
Short-Circuit Protection
No load input current : 0.65mA
2.54mm pin pitch, Arduino Breadboard MCU Development Board friendly
Excluding Pin Size 11mm x 7.62mm x 4.5mm(small)
Weight : about 0.5g(Very very light)