Are you looking for a professional, yet affordable DC-DC step-down module? Are you in search of a sturdy, trustworthy tool that can do multiple jobs at once? If yes, look no further Our professional DC-DC step-down module must meet you needs. It is one of the best choices for you. Features - Color: Blue. - Material: Plastic, metal. - Size: 2 x 1 x 0.5 cm/0.8 x 0.4 x 0.2 inch. - Input voltage: DC 4.2 V-10 V. - Output: 3.3 V, 800 mA. - Boost modules or buck module indicate the operating voltage, Please donot exceed operating voltage , or it will be damaged easily - Boost module output voltage can only be greater than or equal to input voltage, cannot be less than the input voltage - Buck module input voltage must be higher than output voltage of 1.5V or 2V, otherwise it can not output enough power - Automatic Adjustable Boost or Buck module has start voltage and limit working voltage, Please donot exceed them , or it will be damaged easily - Cannot reverse polarity , or it will be short circuit, or will be born easily