Unlike heat shrink splices, there's no need for a high-heat source which can damage the splice, just unwind the inner core. Just unwind and go.
The cold shrink splice body is designed to help minimize installation errors by allowing for greater mispositioning errors or mistakes in insulation length removal, compared to push-on splices.
Each individual 3M splice body is factory tested using two production tests, and have an excellent field-tested track record.
The brands listed above are trademarks of 3M.