https://www.trekbikes.com/us/en_US/promo-collections/always-on/c/E430/?utm_source=bm23&utm_medium=email&utm_term=See+Daytime+Running+Lights&utm_content=See+Daytime+Runnin g+Lights&utm_campaign=US+Consumer+201808XX+ABCs+-+A+-+Always+On+DRL

well I don't own one of these or used them myself I see them in use and they appear quite bright to me. And I thought it was a statement in itself that Trek makes such a big deal out of providing this daytime running light and these have caught my attention often so they work on me at least .