Katushka2S is the next generation of far-red fluorescent protein TurboFP635 (Katushka) [Luker et al., 2015; Shcherbo et al., 2009; Gurskaya et al., 2011]. Katushka2S exhibits highest brightness, fastest maturation and superior signal-to-noise ratio compared to TurboFP635 and many other available far-red fluorescent proteins: E2-Crimson, mNeptune, mNeptune2.5, mCardinal, TurboFP650 and NirFP [Luker et al., 2015], which makes it the protein of choice for visualization within living tissues. Katushka2S can also be used together with iRFP720 [Luker et al., 2015] for dual color whole body imaging.