Edit 06/27/24 - I am now giving the light 5 stars. I used the light a few times on rides since this review and did not get the dimming effect. the light maintained it's initial brightness. I suspect the dimmer is a protection feature when there's overheating.Secondly, I did hear back from support and they confirmed that it's likely the overheating protection feature kicking in.I have upped my rating to 5 stars since the unit operates as intended, is VERY bright and has a secure installation point and easy to aim. The light spread is wide and illuminates a lot of the path ahead. It is also priced affordably!I do not hesitate to recommend this light!Initial Review:Brightness - The most important factor when choosing a light... initially it is very bright and very impressive, but after riding for 3-4 minutes, it dims to less than half-power. Shutting it off and on again restores the light to full brightness once more, however, the it dims again within 30 seconds. Did this on-off process a few times with the same result.Warranty - I did not use the light until day 31 of ownership so I could not return it : ( However, I did send an email to inquire about a possible claim for replacement under warranty. It's been 5 days and no response yet... I just sent a follow up email.I will update this review if the situation improves.