Encyclopedia
Bickford cord
Bickford cords (slow-burning cords or Bickford cords) are devices designed for transferring flame towards a regular primer or detonator. They usually consist of a thin sheath made of textile material impregnated with pitch, rubber, or plastic, containing a linear (along the entire length) charge of black powder inside
Source: "Explanations to the Harmonized System of Foreign Economic Activity Goods Nomenclature of the Russian Federation (HS RF)" (prepared by the Federal Customs Service of Russia) (volume 2, sections VI - XI, groups 30 - 63)