The ones I have will stay lit for about 40 hours before the batteries die. You have to turn them off manually. The Tracer nock brand has 2 different styles. One called a target model stays on for 30 seconds after activation and the other stays on until it is manually turned off. I have shot both brands and the only drawback I see to the Tracer brand is the weight. The ones for my ACC 3-60's weigh in at a healthy 51 grains where as the BC Lumenoks are 31 grains.