This product does not include power supply, need to bring their own. use the mobile phone charger to supply power, -USB interface. The charging treasure requires a small current supply mode, otherwise the charging treasure will turn off the output because the current is too small.Only the IN-12 glow tube is supported. IN-12a or IN-12b can be used. Plug the tube into the socket and use it. Be careful that the tube pins are straight and be careful not to insert . The product is the default hair IN-12BThis product uses a glow tube to display 4 bit time in turn, no 4 bits so intuitive, using clock chip, timing accurate, and with test tube function.Battery is not included because of security issues.The size is 5cm in diameter.Colour:As ShownMaterial:plastic+metalPackage Contents:1 x IN-12 TUBE clockOnly 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.