diff --git a/misc/dispersion-SVD.py b/misc/dispersion-SVD.py
index e53027f..e9099c3 100755
--- a/misc/dispersion-SVD.py
+++ b/misc/dispersion-SVD.py
@@ -22,8 +22,8 @@ parser.add_argument('--output', action='store', help='Path to output PDF')
 parser.add_argument('--nSV', action='store', metavar='N', type=int, default=1, help='Store and draw N minimun singular values')
 parser.add_argument('--background_permittivity', action='store', type=float, default=1., help='Background medium relative permittivity (default 1)')
 parser.add_argument('--sparse', action='store', type=int, help='Skip frequencies for preview')
-parser.add_argument('--eVmax', action='store', help='Skip frequencies above this value')
-parser.add_argument('--eVmin', action='store', help='Skip frequencies below this value')
+parser.add_argument('--eVmax', action='store', type=float, help='Skip frequencies above this value')
+parser.add_argument('--eVmin', action='store', type=float, help='Skip frequencies below this value')
 parser.add_argument('--kdensity', action='store', type=int, default=66, help='Number of k-points per x-axis segment')
 #TODO some more sophisticated x axis definitions
 parser.add_argument('--gaussian', action='store', type=float, metavar='σ', help='Use a gaussian envelope for weighting the interaction matrix contributions (depending on the distance), measured in unit cell lengths (?) FIxME).')