The Asura Dynamics 2DPS Flash Light replicates the Russians real steel flashlight which they apply to many of their AKs. If a flashlight has the "S" suffix in its model designation, for example, the 2DPS Flashlight, that means it has a strobe function. So the 2DPS flashlight comes with strobe which is a very useful function when it comes to temporarily blinding your opponent.
Disclaimer: All aftermarket upgrade parts require necessary skill or modification to install and assemble, please consult with your airsoft technician if needed.