Hey @DeKay,
Cable "pants" are specialized heat shrink, which make the transition from the outer cable jacket to the individual + and - conductors more tidy. Sometimes instead of heat shrink they are are little barrels with 1 in and 2 or 4 out. They can look pretty fancy but are also pretty heavy.
The kind I ordered fit OK on the jacket, but the legs were too small for the dual 12 gauge conductors that needed to fit each.
PS - Parts Express has the 2 conductor Mogami 3103 per foot.