A heat shrinkable plastic sleeve having an inner surface deformed in circumferentially spaced portions by unequal amounts from its normal heat stable or unstable configuration so as to provide different stresses in the circumferential direction whereby uniformity of heating of the sleeve throughout its...http://www.google.ca/patents/US4804733?utm_source=gb-gplus-sharePatent US4804733 - Thermoshrinkable tube means for controlling uniform heating thereof and process for fabricating such tube
