Noble Sail
A Noble Sail is a device that harnesses a specific type of charged particle found only in the Nephon Sector, called a Noble Particle.
Noble Particles are energetic, with either a positive or negative charge, which refers to the direction they are moving relative to the Hoked Nebula, which seems to be their origin. A Noble Sail harnesses these particles in a large, net-like device, and funnels them through accelerators.
As a result, a Noble Sail allows continuous acceleration with little fuel expenditure.
Due to not-fully-understood properties of Noble Particles, a Noble Sail seems to bend relativistic rules, and Noble Sail-equipped ships have been known to reach significant speeds above M. The "Mifune 5" out of Toko set the speed record for the Sector with 4.12M.