Here is the
crimper that we have found to love over the years.
Shop around though, there are many vendors for these types of connectors. Remember that the cases can be reused and you have the option of only replacing the
contacts.
Amazon typically has good deals on the connectors.
45A 10pack
30A 100pack
We have had few issues over the years. They stay connected well by themselves, but you can also run a zip between the two sets of connectors to keep them secured. Not a bad habit to get in.