Shinwa Sokutei Laser Receiver II Plus for Green Lasers with Holder 71501 Quantity: 1 Body Size: 150 x 67 x 34mm Reception Distance: 1.5m ~ 20m Center Reception Width: Narrow Mode: Within ±1.0mm from the center reception line; Wide Mode: Within ±2.0mm from the center reception line Auto Power Off: Automatically turns off approximately 7 minutes after power on Battery Consumption Warning: Warning via flashing power LED Power Supply: 1 x 9V alkaline dry cell battery (The included battery is for monitoring purposes, and its lifespan may be short.) Continuous Operating Time: Approximately 20 hours Application: For marking lines in bright environments or locations where laser lines are difficult to see from a distance.