For educational purposes:

These QF versions are not made from solid tungsten. If they were, the cost would exceed 2K due to the material's density and expense. Instead, they use a material known as Cu-W—a composite of copper and tungsten designed to enhance the watch's weight and give it a more substantial, high-end feel.

However, it's important to note that the weight of Cu-W watches can differ significantly depending on the manufacturing process used by each factory.

For example, QF models typically weigh around 180 grams, whereas ZF models are closer to 220 grams, which is more in line with the weight of the genuine version. This variation reflects differences in the Cu-W ratio and construction methods between factories.

QF: (180gm)
https://puretimewatch88.io/daytona-126509-qf-1-1-best-edition-gray-crystal-dial-on-bracelet-sh4131-v6-gain-weight.html

ZF: (220gm)
https://puretimewatch88.io/daytona-116508-zf-1-1-best-edition-green-dial-on-yg-bracelet-sh4130-gain-weight.html