From Amazon
MAUL Ferroband, self-adhesive magnetic wire wall rail, white, 6210502
Conrad Electronic
Maul Magnetic tape Ferroband (L x W) 5 m x 3.5 cm White 5 m 6211002
Kaiser Kraft
MAUL width 35 mm, roll length 5 m, pack of 3, width 35 mm, roll length 5 m, pack of 3, white