  In this letter, we investigate the properties of a strongly interacting
spinless Fermi gas close to a $p$-wave resonance. We show that the universal
properties at a $p$-wave resonance are captured by two contacts, which are
related respectively to the variation of energy with the $p$-wave scattering
volume $v$ and with the effective range $R$ in the two adiabatic theorems
derived. We show how the two contacts determine the leading and sub-leading
asymptotic behavior of the momentum distribution ($\sim 1/k^2$ and $\sim
1/k^4$) and how they can be measured experimentally by radio-frequency, Bragg,
and photo-association spectroscopies. Finally, we evaluate the two contacts at
high temperature via the virial expansion.
