Two preprints were posted to the arXiv over the weekend, both studying the exciton-mediated reflectance of monolayer MoSe2. The research groups, one at ETH Zürich and one at Harvard, find maximum reflectance up to 0.85 for hexagonal boron nitride encapsulated monolayers. The reflectance is electrically switchable at high speed. On the other hand, the incident light must be ~755 nm (equivalently, ~1.64 eV), and the mirror must be held at cryogenic temperature. Nevertheless, this appears to be an enticing optical system.