Atto 620 is a new label with high molecular absorption (120,000) and quantum yield (0.50) as well as sufficient Stokes shift between excitation and emission maximum. Atto 620 is characterized by a high photostability.

Atto fluorescent labels are designed for high sensitivity applications, including single molecule detection. Atto labels have rigid structures that do not show any cis-trans-isomerization. Thus these labels display exceptional intensity with minimal spectral shift on conjugation.