4, Power supply alarm indicator. The LED on the front of the transmitter indicates the condition of the batteries. It will flash green during operation if the battery power is sufficient and will flash red if the battery power is low.If the LED is flashing red, or if the operation becomes erratic, or will only work from a short distance, replace both batteries with new AA alkaline batteries. Thank you for your support. We are not responsible for undeliverable address. Dear friend, your happy is very important to me! We stand behind every product we sell. You can enjoy top-quality product and high-quality services from us, Trust me that you will have a pleasant shopping experience in here. We will be happy to assist you. We would try our best to serve you with any question / problem. This item is in the category "Business & Industrial\Material Handling\Hoists, Winches & Rigging\Lifting Machine Parts, Rigging\Lifting Machine Remotes". The seller is "keymei2015" and is located in this country: CN. This item can be shipped worldwide.