Electronic bugging devices.

5 seconds sound clip from the Batman (1966) TV series - Fine Feathered Finks (S1E3).

You can hear this line at 00:20:50 in the Blu-ray version of the movie.

Quote context

[...]

- He's given us a clue to his plot and we can't solve it.

- If only we had some way of spying on him.

- Well, that's it, Robin. You've done it again.

- No kidding?

- Look, listen.

- Electronic bugging devices.

- A perfect, lifelike spider.

- Right. Only it's not a spider. It's a tiny microphone with a built-in super power transmitter.

- Exactly. I'm going to take it.. And drop it in the Penguin's shop. We'll listen in to his crooked scheming.

- It's a great idea, Batman, but.. How'll you get away with planting it? Won't he be on guard against you?

- Of course. He'll be on guard against Batman. That's why I'm going to visit his shop as Bruce Wayne.

[...]