That's the stuff. But my query is whether I need it? I can't see what it does apart from melt.. it doesn't seem any more heatproof than the cable itself and all it does it make the cable hotter by getting hot/melty itself and being in close proximity?
Lead is proper fucked ;)
Do you mean that black crinkly stuff?
Then auto factors usually have this stuff on a roll. But finding one near you.