For joining cables use this RS part 391-980, a solder sleeve that shrinks and provides environmental sealing.
For the adhesive lined ones look at 157-3852, works well, and especially for a battery terminal provides extra corrosion proofing, as then acid will not find it so easy to migrate under the sleeve and corrode the wire from inside and migrate up the wire, corroding it as it goes up.
As well with the crimping tool, the insulated crimping tool you showed has a directionality, as the dies are shaped so as to provide an oval crimp on the copper tube and a star pointed crimp on the insulation, so that the copper of the tube is crimped to the cable evenly while the insulation is gripped in 4 places to provide strain relief. Put them in backwards and they do not crimp as well. The uninsulated ones do not have this need, so can go in either way, providing the crimp indent is at the middle of the tube, it can go anywhere in the tube but is best on top for consistency, so it is easy to check all have been crimped. Better tools use a 6 sided tool, that crimps the tube all around to reduce the diameter in the middle so as to get the high pressure that makes a gas tight connection.
