Accuracy of mass profiles created via slices following Schramm (1994) compared to an analytical SIS. Top: Radial convergence profile of a SIS (blue line) and of ‘ElliSLICE’ mass models using 10, 20, or 60 slices (dash-dotted orange line, dashed green line, and densely dashed red line, respectively). Bottom: Residuals in percent between the SIS profile and profiles made of slices. The vertical black line indicates the Einstein radius.