This blood pressure cuff is called Microlife and uses oscillometry rather than mercury sphyngmomanometry as the measuring mechanism. This is reportedly much more accurate for measuring preeclampsia. It was developed by Tommy's, in the UK, and specifically designed for low-resource settings. The blood pressure cuff meets WHO standards for low-resource settings.
Tommy's is also developing a solar-powered version of this device for the WHO and costs about $30 US.