1.Without anti-backflow function, the output end is connected to the anti-backflow diode to charge rechargeable batteries(If you are a professional, you can not connect the anti-backflow diode) 2.With MPPT function, support MPPT solar charging 3.Can connect external temperature probe to support over-temperature protection. Stick the external temperature probe on the battery to automatically stop charging when over-temperature 4.Note: This product has no output reverse connection protection. Reverse connection of the positive and negative poles of the battery damage the device. Battery charging requires certain professional knowledge. Non-professionals should not charge directly to prevent fire and explosion Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Color: As Shown Material: PCB+Plastic+Electronic Components Package Contents: 1 x DC buck-boost power supply Base Plate 1 x 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 little different from the real thing. The measurement allowed error is +/- 1-3cm.