Any intelligent device for USB interface (computer, TV, music player, punch card machines), can do the tolerance test. And suitable for mobile phone with OTG. Portable battery, mobile phone charger, public charging station, etc. is mostly invalid. There is a risk of damage, be careful to test. In short circuit test, do not short-circuit continuously for more than 20 seconds, will be damaged due to high temperature. Output high voltage, do not touch. NOTE:This product is used for USB interface pressure test, can not be used against the and behavior testing and research, any disputes and adverse consequences shop is not responsible for, consider carefully buying The product is used to test the resistance of any device with USB port (computer, TV, music player, attendance machine, etc.) to electrostatic damage. Input voltage: 4.5 - 5.5 V DC Output voltage: -215 V DC Pulse Frequency: 4 - 8 / second Pulse current: 180A Note: High voltage, power must be off after standing for 2 minutes, until the release of more than electricity, and then carefully openings on the motherboard After more than 20 seconds off electricity to about 100V, 70 seconds after to less than 30V Then you can touch the board. The for interface OTG connector only can be used time, after the for interface is burned by the USBkiller , the for interface OTG connector will be broken, and the for interface connector needs to be replaced the use. Colour:random color , 't accept the specified color Material:plastic+metal Package Contents: 1 x USB 1 x Tester 3 x Adapter connector 1 set x Accessories Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.