Mattel is coming out with three new body shapes for its iconic Barbie doll, after facing longstanding criticism over the toy's unrealistic proportions. As Time reports, the three new models — known as tall, curvy, and petite — are available today on Mattel's website, alongside the classic version, and will hit store shelves once the toy company negotiates for shelf space at retail outlets.

The move comes amid slumping sales for the Barbie doll, which made its debut in 1959. Evelyn Mazzocco, head of the Barbie brand, tasked her team with developing new models in 2014, in an effort to more accurately reflect women's bodies. Expanding to three body types has posed logistical challenges; the company will sell two different shoe sizes to accommodate the different models, and they'll be sold together in a set to "optimize diversity and marketability," Time reports. The company also spent considerable time deciding on what to call each new model.

Barbie's proportions have changed slightly over the years, but Mattel has continued to face criticism for promoting an unrealistic body image to girls. The company has largely deflected criticism in the past, arguing that the doll's various career choices — doctor, astronaut, businesswoman — support female empowerment, and denying that Barbie influences girls' body images. Barbie design VP Kim Culmone defended the doll's longstanding design in 2014, saying: "Barbie’s body was never designed to be realistic. She was designed for girls to easily dress and undress."

Mattel has not disclosed the exact proportions of its new Barbie models, and although the company acknowledges that the new designs may not satisfy everyone, it hopes they'll at least dull one of the brand's most persistent criticisms. "Yes, some people will say we are late to the game,” Mazzocco tells Time. "But changes at a huge corporation take time."