Lay Flat Tubing (Cranbourne RG21)

Lay flat tubing 20cm width, so the open diameter is 12.7cm, circumference is 40cm.
Length is many, many meters.
It’s a heavy gauge plastic.

Essentially, lay flat tubing is continuous soft polythene tubing that is flattened and sold on a roll. You can cut it to any length to pack things of different lengths, sealing the ends with a heat-sealing device, or secure with tape, tie-wraps, etc, for storage or sales shipping.

This is most often used by businesses, but I last used it for storing my Christmas lights without them tangling.