Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Hard to remove

I have had this filter for over a year. It works as advertised. I have taken beautiful photos with that classic polarized sky and lush green vegetation. But, and it's a big BUT, it is nearly impossible to remove from my Canon 28-135 lens. There is no knurling that allows your fingers to grip the threaded frame that screws into the lens barrel. In fact, it fell apart while taking it out. I had to put it back together (an adventure in itself). The lubricant that is used for the rotating mechanism ended up on the glass and now it is unusable. I would recommend against this filter for that reason alone.