  We have discovered a new, near-equal mass, eclipsing M dwarf binary from the
Next Generation Transit Survey. This system is only one of 3 field age ($>$ 1
Gyr), late M dwarf eclipsing binaries known, and has a period of 1.74774 days,
similar to that of CM~Dra and KOI126. Modelling of the eclipses and radial
velocities shows that the component masses are $M_{\rm
pri}$=0.17391$^{+0.00153}_{0.00099}$ $M_{\odot}$, $M_{\rm
sec}$=0.17418$^{+0.00193}_{-0.00059}$ $M_{\odot}$; radii are $R_{\rm
pri}$=0.2045$^{+0.0038}_{-0.0058}$ $R_{\odot}$, $R_{\rm
sec}$=0.2168$^{+0.0047}_{-0.0048}$ $R_{\odot}$. The effective temperatures are
$T_{\rm pri} = 2995\,^{+85}_{-105}$ K and $T_{\rm sec} = 2997\,^{+66}_{-101}$
K, consistent with M5 dwarfs and broadly consistent with main sequence models.
This pair represents a valuable addition which can be used to constrain the
mass-radius relation at the low mass end of the stellar sequence.
