Piston head bearing in ergal with double or lightened for high speed (TPAVN).
This head is specifically designed for fast gusts, both for its very low weight and for its very low resistance to air recirculation inside the cylinder.
In practice, this head is designed not only to maximize the compression of the forward air, but also to facilitate its restoration when the piston moves back.
All this avoids the drop in power due to the low air pressure during the fastest gusts.
Weight: 0.002g