Does Parallax PING sensor have built in resistor?

Hi everyone, I'm a complete nube so I hope my question isn't completely daft but does the Parallax PING sensor have a built in resistor or do I have to put one in the circuit between it and the arduino board. The specs say it wants 30 milliamps supply but nowhere can I find any reference to whether it has the resistors already or I need to add them.

Thanks

The board will take the current it needs, no need for current limiting resistor.

OK great! It seems to be working perfectly just hooked up directly to the arduino. I didn't want to fry it! This is some cool stuff but a steep learning curve for me, I hope to make some robots once I get the basic down.