  We compare the vacuum measured by two portable cold-atom vacuum standards
(pCAVS) based on ultracold $^7$Li atoms. The pCAVS are quantum-based standards
that use a priori scattering calculations to convert a measured loss rate of
cold atoms from a conservative trap into a background gas pressure. Our pCAVS
devices share the same laser system and measure the vacuum concurrently. The
two pCAVS together detected a leak with a rate on the order of $10^{-6}$ Pa
L/s. After fixing the leak, the pCAVS measured a pressure of about 40 nPa with
2.6 % uncertainty. The two pCAVS agree within their uncertainties, even when
swapping some of their component parts. Operation of the pCAVS was found to
cause some additional outgassing, on the order of $10^{-8}$ Pa L/s, which can
be mitigated in the future by better thermal management.
