To facilitate deflation, the best way is to "pinch" the "anti-return" valve in the open position inside the mattress, with one hand, and roll the mattress with the other hand.
Once the pressure is reduced in the mattress, thanks to the flow of air outside, the "anti-return" valve no longer blocks itself and it becomes very easy to finish emptying and folding with 2 hands.
A score for comparing products' environmental impact
The product's environmental impact is calculated over its entire life cycle using different indicators. A score from A to E is provided in order to easily identify the most eco-friendly products by comparing products of the same type (T-shirts, trousers, backpacks).
Decathlon actively promotes this environmental rating initiative.
Explanatory video: https://youtu.be/8t63KkRwn_8