The red flash lenses make it possible to hide the eyes of the hunter on the one hand,
which is well appreciated for tracking certain predators, such as the Denti for example,
which is particularly sensitive to the movement of the hunter's eyes.
This type of glass also increases the contrasts under water,
and to have a better discernment of forms.
Nevertheless, this type of glass is still recommended for clear water.
Its use in charged water should be avoided.