SPLE parameters for the galaxy acting as main gravitational deflector to FBQ 0951+2635. The lines in green and red result from the astrometric constraints in APS 1 (see Table 2; Jakobsson et al. 2005) and APS 2 (see Table 2; Sluse et al. 2012a), respectively. Top left panel: Power-law index. Top right panel: True mass scale. Bottom left panel: Ellipticity of the mass distribution. Bottom right panel: Position angle of the mass distribution. Our solutions for e and θ_e are also compared with the observed (near-IR) morphology of the galaxy. The light green and light salmon rectangles represent 1σ intervals in APS 1 and APS 2, respectively.