With double-sided anti-drip, the squeegee is folded against the squeegee when printing and the squeegee against the squeegee when flooding.
This prevents ink/paste from dripping into the open or flooded screen, which would impair print quality.
The double-sided folding anti-drip device is mainly used for inks / pastes with low viscosity. It is also used for special applications with fluoroscopy, e.g. electroluminescence.