Features: brand new and high quality 1.Boost modules indicate the operating voltage, Please donot exceed operating voltage , or it will be damaged easily 2.Boost module output voltage can only be greater than or equal to input voltage, cannot be less than the input voltage 3.The module input voltage must be higher than output voltage of 1.5V or 2V, otherwise it can not output enough power 4.Automatic Adjustable Boost module has start voltage and limit working voltage, Please donot exceed them , or it will be damaged easily 5.Cannot reverse polarity , or it will be short circuit, or will be born easily Specifications: Size:approx 8.6mm x 12.33mm/3.39x4.84in Input voltage: For DC 4.2 V-10 V Output: 3.3 V, 800 mA Uuantity: 5PCS Note: (Without retail package) Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-1cm error due to the manual measurment. Package includes: 5PCS x DC-DC Step-Down Power Supply Modules