  Several puzzling regularities concerning the low temperature excitations of
glasses are quantitatively explained by quantizing domain wall motions of the
random first order glass transition theory. The density of excitations agrees
with experiment and scales with the size of a dynamically coherent region at
$T_g$, being about 200 molecules. The phonon coupling depends on the Lindemann
ratio for vitrification yielding the observed universal relation $l/\lambda
\simeq 150$ between phonon wavelength $\lambda$ and mean free path $l$.
Multilevel behavior is predicted to occur in the temperature range of the
thermal conductivity plateau.
