This is a tightly woven glass cloth suitable for wing and tailplane covering when used with a finishing epoxy such as the BSI Finish cure.
Some builders and competitors use this weight glass cloth to add even more strength and stiffness but there is a weight penalty for this.
Glass cloth covering adds strength and stiffness to the wing and tailplane and this in it's self aids performance. The finish is more durable and the model will last longer.
Just about any paint system can be applied over a glass cloth finish.