This package contains only 1pc 4000mAh battery, which can display battery. Note: We have made improvements to the battery. The previous battery did not have a digital display version, but the subsequent batteries have been changed to a digital display version. Some machines in the Polish warehouse have non digital display batteries. If you have any questions, please contact customer service. Waterproof/dustproof: IP54 Laser Class: Class 2 Wavelength: 515nm. Power supply: Rechargeable 4000mAh Lithium Battery. Operation time (All laser lines are on): About 5-7 hours. After turning on the laser power, switch the power and press the operation key to select the laser beam mode. When the inclination angle of the instrument exceeds 3º, the laser ray will flash quickly and alarm so that whether the locating place of the instrument is even or not can be detected. >>Manual mode (Slope mode). On state, long press the “receiver” key, no flickering and no alarm, you can continue to operate to select the laser beam and can be operated at the angle you choose. How to use the receiver with K36G laser level? 1: First, turn on laser level’s pulse mode–press once the “receiver” key, the laser line becomes weaker and then enters the pulse mode. 2: Second, turn on the receiver and search the laser lines.