I am not sure what others are referring to when they suggest that the heat sinks are cheap and easily broken off. I manhandled these bulbs trying to get them into their sockets and the heat sinks withstood all of the strain and scraping with little signs of damage.

That being said, these do fit the 2015 Prius low beam headlight sockets, but they are a tight fit. I mangled my hand trying to get them in without taking anything apart. That didn't work on the passenger side. You absolutely need to remove the two bolts holding the coolant tank and then you need to pull back the coolant bracket so that you can get just enough space, with minimal scraping on the bracket, to put this bulb into the low beam projector socket.

They are definitely bright enough at night as far as I am concerned. I don't need my low beam to act as high beams.

However, I should note that while they do work out of the box, they need to be installed with positive and negative plugs on the correct female power sockets. This means that you will need to trial and error by turning on your headlights and seeing if the bulbs illuminate. If not, then flip the power connector the other way.

Another thing I noticed is that when these bulbs are plugged in, I can no longer use my daylight running hid lights for cars. There is some technical issue that prevents them from being used with these bulbs. However, these bulbs last 30,000 hours and require a fraction of the energy to power them, so I think I will be fine using them as my new DLRLs as well as headlights.

I will update this review if there are any reliability issues.