Kontakt is a sampler created by Native Instruments that allows for any type of sample library to be easily used in a DAW or standalone. You load Kontakt, then inside Kontakt you pick a sample library, then you can use that library via MIDI notes.
Soundblind Drum Libraries use Kontakt to deliver the highest quality, mix-ready drum samples. We also use Kontakt because of how easy it is for the user to download and access the library through Native Access.