This is a cap that slides over the Wurkkos TS28 flashlight to protect the lens and the button from damage when you store it in a bag with other items.

The button cover also helps prevent the flashlight from turning on accidentally, so you don’t have to lock and unlock it every time by pressing the button four times.

If you’re looking for a flashlight with great throw at a good price, it’s hard to find a better option than this one. 

If you’d like to buy it, you can find it here (affiliate link): https://s.click.aliexpress.com/e/_c4CqDXUj or on amazon https://amzn.to/4cWbfVZ 

For a shorter-throw flashlight, I recommend the Wurkkos TS26S: https://s.click.aliexpress.com/e/_c2yi6NWX or on amazon https://amzn.to/42mydzq 

These come with a solid 5000mAh 21700 battery, but if you need an extra one, I recommend these (I tested the capacity and it matches the advertised 5000mAh): https://s.click.aliexpress.com/e/_c4lofr2R