SPY650-FastActâ„¢ is a bright, far red, fluorogenic & non toxic F-actin stain based on SPYâ„¢ dyes series. Its optimized structure allows to label F-actin in live cells with high specificity and low background. The unique and unmatched feature of SPY650-FastActâ„¢ is its ability to label very dynamic actin, like LifeActâ„¢* but the probe does not require any genetic manipulation, transfection or overexpression of fluorescent proteins. SPY650-FastActâ„¢ is based on our bright, photostable & far red SPY650 fluorophore which is far superior than fluorescent proteins. SPY650-FastActâ„¢ enables multicolor imaging with SPY505, SPY555, SPY595, SPY700, GFP or m-cherry. SPY650-FastActâ„¢ can be imaged with standard Cy5 filterset. It can be used for widefield, confocal, SIM or STED imaging of living cells and tissue.*LifeActâ„¢ is a registered trademark of Ibidi GmbH.