We report the final results of the ALPHA collaboration for some B-physics observables: $f_B$, $f_{B_s}$ and $m_b$. We employ CLS configurations with 2 flavors of $O(a)$ improved Wilson fermions in the sea and pion masses ranging down to 190 MeV. The b-quark is treated in HQET to order $1/m_b$. The renormalization, the matching and the improvement were performed non-perturbatively, and three lattice spacings reaching $a=0.048$ fm are used in the continuum extrapolation.
