SiR700-actin is based on the far-red silicon rhodamine (SiR) fluorophore analogue SiR700 and the actin binding natural product jasplakinolide. SiR700-actin allows labeling of endogenous F-actin in live cells with high specificity and low background without the need for genetic manipulation or over-expression. The key features of SiR700-actin are i) far-red absorption and emission wavelengths, ii) cell permeability, iii) fluorogenic character, and iv) compatibility with super-resolution microscopy (e.g., STED & SIM). In addition, SiR700 actin can be used for wide-field and confocal fluorescent imaging in living cells. The emission in the far-red wavelength minimizes phototoxicity and sample autofluorescence. SiR700-actin is compatible with GFP and/or m-cherry fluorescent proteins. It can be imaged with standard Cy5 filter sets. Probe quantity allows 35 – 140 staining experiments.*