The red wire is connected to the positive battery terminal, and the black wire is connected to the negative battery terminal. Easy to install,locks on you battery very well. The products are only used for flexible conversion between one tool and another lithium battery, and do not involve any other ! The products are only converter, not charger, not battery, not machine, also can not recharge battery by it. Note: Due to different production batches, labeling is random and does not accept designation and does not affect use. Installation guide not included, we strongly recommend you professional installation. Please check as much as possible to make sure the item is what you need. Tips:The product may be updated constantly,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use. Applicable For battery model: 18V Lithium Battery: BL1815,BL1830,BL1830B,BL1840,BL1850,BL1860. Color:Blue Material:plastic Package Contents: 1 x Adapter(No Battery) 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.