This Mikasa Ackermann vinyl figure is released by Funko in their POP! Animation x Attack on Titan vinyl figure series.
Funko POP! is a crossover vinyl figure series by Funko and other famous franchises such as Disney, Pixar, DC Comics, Marvel Comics, Simpsons, South Park, Uglydoll, etc. Each POP! figure is about ~3" to ~5" tall and crafted in a Japanese anime/manga super-deformed style (NOTE: due to the unique design of each character, the actual size of the figures may be smaller or bigger than stated).
The POP! Animation x Attack on Titan features characters from the popular anime, which is set in a world where human lives in cities surrounded by enormous walls as a defense against the Titans, giant humanoid who seem to eat humans without reasons.