Item: Bicycle spoke light, bike wheel LED string, décor light Length: 2.2 meter, approximately 7 feet; one LED light string for one wheel LED quantity: 20 Mode: on, fast blinking, slow blinking, off Controller dimensions: 66*30*23 millimeter, approximate 2.6*1.2*0.9 inch Controller color: Black or silvery white, pick randomly when shipment Net weight: 15 g, approximately 0.5 oz. Battery: AA battery, not a rechargeable battery Feature: Water resistant, durable ABS case, light weight, lower power consumption, last for 20 hours by high quality AA battery There is a steel wire inside the battery holder. The steel wire must touch with the round metal piece of the cover.  Screw the cover firmly to make sure it is touched properly.