Descrtion:1.Size: Approx. 15cm/5.9"2.Power Supply: 1 x 1.5V "AAA" Battery (Battery not Included)3.Prince: according to conductivity changes to determine moisture change in brake , with five different color LED indicatorIndicator Descrtion:1.5 LEDs indicating the water % in the brake :2.0% light indicates that the battery is OK, no repment3.1% light indicates that moisture content of brake oil le than 1% , brake has a good performance, and ease of .4.2% light indicates that moisture content of brake oil le than 2%, brake can be continued to 5.3% light indicates that moisture content of brake oil le than 3% , proposed to rep brake .6.4% light indicates that moisture content of brake oil le than 4%, brake should be repd immediately.7.Note: Due to the difference between different s, the ture may not reflect the actual color of the item. Thanks for your understanding.Package Included:10x Brake TestNote : this product comes without retail boxes,We put in a safe pack(Note:Just as the Custom probl recently,some orders can not pa the cheas the battery,and many packages were retuned,as this reason,we remove the battery,if you need the battery,you can buy one in your local area.Hope you can understand that)To Che Quality:Pre the on for power on, green LED will light up.Insert the into reservoir for a second , then the results will be indicated correctly by LEDs.Auto power off .