What connector do I need to match my existing test leads?
These are generally standard 4mm banana connectors. The specific ones you show are shrouded ones. They need to be shrouded in order for your multimeter to meet its safety specs. For the male connectors, standard connectors can be used in jacks designed to take shrouded ones. In the other direction, this is not the case - a shrouded plug cannot go into a unshrouded jack (because the shroud will be in the way)