Lincoln and Clyde each have walkie-talkies that they use to talk/communicate with each
Clyde and Lincoln are shown to use radio transmission talk. They say phrases like, "Over and out", and "Roger that".
They are purple, with a green circle with "A!" written on them, and they have two red knobs on top. On the bottom of the walkie talkies, there are two black screws. They have a red Push-To-Talk button on the side, and they have long, black antennas, with a green spheres on top. In the middle, they have a gray speaker in the middle.
Despite both of them having smartphones, their walkie-talkies are their primary form of communication. This is probably because they had them before they got the phones, and it is easier to contact each other.