https://borisfx.com/faq/sapphire-trial-watermark/

All free Sapphire trials have a watermark. The Sapphire trial version is a fully functional 30-day trial watermarked with a red X. We designed the watermark to be as unobtrusive as possible so the effects can be properly auditioned and experienced. After the 30-day trial times out, Sapphire will begin to render black frames. If you purchase a Sapphire license, the watermark will disappear and Sapphire will begin to render perfectly.

Download your free Sapphire trial.