Glaze Supply general purpose masking tape, 40mm x 50m. Ideal for protecting windows, skirting boards and other areas while painting or spraying. Masking tape gives a clean edge between the area being painted and the surface you want to keep clear. Apply it to clean, dry surfaces and press the edge down firmly before you start. 40mm is a mid width for general masking. Masking tape is best used on clean, dry, stable surfaces rather than loose or flaking paint. Remove the tape once the work is finished rather than leaving it on the surface for a long time.