In this paper we study equivalence classes of generic $1$-parameter germs of real analytic families ${𝒬}_{\epsilon }$ unfolding codimension $1$ germs of diffeomorphisms ${𝒬}_0:(ℝ,0)\to (ℝ,0)$ with a fixed point at the origin and multiplier $-1,$ under (weak) analytic conjugacy. These germs are generic unfoldings of the flip bifurcation. Two such germs are analytically conjugate if and only if their second iterates, ${𝒫}_{\epsilon }={𝒬}_{\epsilon }^{\circ 2},$ are analytically conjugate. We give a complete modulus of analytic classification: this modulus is an unfolding of the Ecalle...