[mini Dc Voltmeters]total 10pcs, 4 Colors Combined(2pcs Red/yellow/blue/green/white); 0.28 Inch Led Panel; Small In Size And Light In Weight; Wire Is Made Of 28awg Gauge; Install The Hole: 23*10 Mm Approx [2 Connection Methods]3 Wires Are Connected Separately To Measure Voltage And Power(red Yellow Is Both For Pos, Black Is Neg); 3 Wires Are Used As 2 Wires, Connected To Measure Voltage(red And Yellow Can Be Paired For Pos, Black Is Neg) [features]reverse Polarity Protection, Voltmeter Wont Burn Out If Reverse Polarity Is Applied; High Precision; Low Starting Working Voltage; Fine Adjustment Function [note]max Voltage With Yellow And Red Connected Is 40v.to Measure Greater Than 40v (up To 100v) The Yellow Wire Is Connected To A Separate Voltage Source That Is 40v Or Less Colour:multicolor Material:led Package Contents: 10 X Dc Voltmeter Display 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