Some of my low voltage rope light motifs have suffered internal damage (rusting) through water ingress.
Even though they are sold for outdoor use, the seal around the wire entry to the rope light leaves something to be desired on some.
I looked at using silicone to seal the wire entries, but wanted something that flowed better.
This 118ml can was from Altronics and is catalogue number T3135. The lid of the can has a small brush built into it.
Be aware that the can contents have a shelf life. ACL member AAH pointed me to this page. Even if the contents go bad after 12 months, you will still have potentially saved the cost of replacement motifs.
Some people on the ACL forum have said they use it for sealing connections on LED strips, etc.
Here it is applied the the wire entry point. Paint it on and wiggle the wire a little to let it seep in better. At first I was was looking for a clear liquid, but with the black you can see where you’ve done better. The black bits are not noticeable at normal viewing distance or at night anyway.