Combining observations from the New Horizons spacecraft with observations from the Hubble Space Telescope and ground based observatories, 1994 JR1 appears to be a very red KBO with a high surface roughness (i.e. it is probably heavily cratered). 1994 JR1 has a relatively fast rotation period of 5.47 ± 0.33 hours and its diameter is assumed to be ~250 km. Simulations also indicate that the orbit of 1994 JR1 brings it close to Pluto every 2.4 million years. Each close encounter causes the orbit of 1994 JR1 to be gravitationally perturbed by Pluto.
Porter et al. (2016), "Red, Rough, Fast, and Perturbed: New Horizons Observations of KBO (15810) 1994 JR1 from the Kuiper Belt", arXiv:1605.05376 [astro-ph.EP]