This specification covers an irradiated, thermally-stabilized, modified- polyolefin plastic in the form of dual-wall tubing. This tubing has been used typically as a semi-rigid, electrical insulation tubing whose diameter can be reduced to a predetermined size by heating to 135 degrees C (275 degrees F) or higher, but usage is not limited to such applications. Tubing is not flame-retardant and will burn slowly. This tubing is stable for continuous exposure from -55 to +110 degrees C (-67 to +230 degrees F).