Chinese doctors have successfully implanted the world’s smallest and lightest artificial heart that uses magnetic levitation technology into a 7-year-old boy, giving him more time to wait for a heart transplant.

Weighing 45 grams and measuring just 2.9 centimeters in diameter, this tiny device is the size of a regular plastic water bottle cap and is about half the weight of the smallest maglev-powered heart pump designed for adults.

The Union Hospital affiliated to Tongji Medical College at Huazhong University of Science and Technology in Wuhan, Hubei province, said on Tuesday that the boy is now in stable condition and awaiting further treatment, following the operation which was carried out on March 30.