2.5cm (1in) gather heading tape, white,1 woven pocket, variable fullness.

Single sided gather-heading tape in white polyester, can be used to make many decorative headings for curtains and valances such as frilled and puffed headings. Variable fullness but typically curtains need to be made with at least twice fullness to give a pleasing depth of pleat.
Single sided tapes have the pockets on just one side of the tape so a little care must be taken to ensure that the tape is sewn on with the pockets away from the fabric.

One row of cord pockets that will accept metal or plastic curtain rings
two high quality draw cords run through specially designed tubes in the tape to allow easy pleating.
See The Encyclopaedia of Curtains - Revised Edition.

Roll size 100m