3 pounds = 1.36kg It's heavy for most recreational activities, but it might be great for expeditions. If it could be made very durable, it could be beneficial

3 pounds = 1.36kg It's heavy for most recreational activities, but it might be great for expeditions. If it could be made very durable, it could be beneficial for superdeep cave exploration. In such environments there is no light, but often there is rushing wind and water. There is also a critical need for power to keep lights running. While charged batteries can also be brought in from the surface, they have a limited lifespan in the cave, and an expedition therefore needs a continuous supply of fresh batteries to continue.