For a 95mm CPL, the safer recommendations from the community are established filter makers such as B+W, Heliopan, Singh-Ray, Hoya, and Hitech. At this size, their higher-end polarizers are generally all considered good quality, with low color cast and solid performance. Based on the answers, the B+W is a known good choice.

There wasn’t enough firsthand information provided to confirm whether the Sigma CPL matches the B+W in transmission or edge sealing, so it’s hard to recommend it over better-known alternatives.

One important caution: at least one user reported that the Sigma 150-600mm can lose noticeable sharpness with a filter attached, even with a high-quality 95mm UV filter. That doesn’t guarantee every CPL will behave the same way, but it does mean a polarizer on this lens may have tradeoffs beyond the usual light loss.

So: if you need a 95mm CPL, buy from a top filter brand and test it carefully on your lens. B+W is a reasonable choice, but Heliopan, Hoya, Singh-Ray, and Hitech are also worth considering.