 The most efficient way to generate random numbers device independently using a photon pair source based on spontaneous parametric down conversion is by heralding path entangled states between two spatial modes sharing a single photon and revealing non-locality through photon counting preceded by small displacement operations. This method requires higher overall detection efficiencies but is more efficient in terms of entropy per experimental run and can provide higher random bit rates under reasonable assumptions. This article was offered by Vika Prarovivili, P. Sekatsky, J. D. Bankal, and others.