Consumer interest in wearable tech is on the rise, if the success of the new Mi Band 3 is any indication. Its maker, Huami, has announced that the biometric smart wristband has already sold over a million units, just 17 days since its launch.

The first Mi Band, launched back in 2014, took four months to reach that level of sales, while 2016’s Mi Band 2 took two months. The trends point to an L-curve with a strong upwards directory, given Huami’s latest success.

Developed in collaboration with Xiaomi, Huami’s Mi Band 3 features upgraded heart rate tracking, among other features. And it’s entirely buttonless, with users swiping and gesturing to control the device.

In a statement announcing the Mi Band 3’s brisk sales, Huami CEO Wang Huang said the achievement “reflects the growing popularity of our products, our excellent supply chain management capabilities and our deep understanding of the market and target consumer base.” It may also reflect a growing interest in smart and biometric wearables more broadly, though the price of Huami’s offering at about $26 probably helps too.