I bought this 4 years ago. It has been the best ice and snow remover from my windows I have ever owned.
I originally got a set of these when featured on the Grommet site, which was at least 5 years ago. I have not used it a lot since I started working from home in 2020, but it always works great for frost. I generally get the defroster going before tackling ice, but once it starts to melt underneath, this worked fine to help remove it. For those not sure how to use it, the small end with the spiky bits pops out and was marketed to use separately on your mirrors, since the large funnel part may not fit between the mirror and side window. It may also help with breaking up thick frost or ice, but probably only after the defroster is on. Oh, and when the spiky end is removed, it can also work as an emergency funnel. It’s entirely possible these are made more cheaply now than 5 year ago, but I have been happy with mine.