Crater II is an unusual object among the dwarf satellite galaxies of the Local Group in that it has a very large size for its small luminosity . This provides a strong test of MOND , as Crater II should be in the deep MOND regime ( g _ { in } \approx 34 \mathrm { km } ^ { 2 } \mathrm { s } ^ { -2 } \mathrm { kpc } ^ { -1 } \ll a _ { 0 } % = 3700 \mathrm { km } ^ { 2 } \mathrm { s } ^ { -2 } \mathrm { kpc } ^ { -1 } ) . Despite its great distance ( \approx 120 kpc ) from the Milky Way , the external field of the host ( g _ { ex } \approx 282 \mathrm { km } ^ { 2 } \mathrm { s } ^ { -2 } \mathrm { kpc } ^ { -1 } ) comfortably exceeds the internal field . Consequently , Crater II should be subject to the external field effect , a feature unique to MOND . This leads to the prediction of a very low velocity dispersion : \sigma _ { efe } = 2.1 ^ { +0.9 } _ { -0.6 } \mathrm { km } \mathrm { s } ^ { -1 } .