こちらの商品は、ストリームライトの専用キャップです。目的はLEDの保護と光束(ライトの光る幅)のコントロール。具体的には拡散せず光をまとめることができます。ただし、商品の性質上(材質の問題か？)使用中にゆるくなって外れることもあります。そこだけ注意すれば使い勝手は良いものかと思われます。

Genial para el trabajo contra incendios

This is the second one of these lights I have purchased in the last five years (at least) because I like them so much. I killed the first one when I "lost" it and then found it after the batteries burst in it. I use it for work for the intense UV light. Very effective even in daylight. Others I have seen need to be used in shade or darkness. If I lose this one, or if the batteries burst, I will definitely buy it again.

Great purchase

I purchased both the Yellow & Black Dualie. The magnet on the butt-end of the Black Dualie was not very strong. The Yellow Dualie was strong.
Reordered another Yellow one. Keeping my fingers crossed.