As seen in Star Wars: A New Hope

I purchased this online, from Master Replicas.

Quite possibly the coolest working prop in my collection, this thing kicks major butt. When you hit the ignition trigger, the blade "grows" up the length of the plastic tube via an array of ultra bright red L.E.D.s. As this happens, the signature "Snap/hiss" noise is issued. The start up sequence alone is worth the price of admission, if you ask me. At just under 100 bucks, it's a pretty nice price too. When you wave the saber around, the sound effects change to match your movement. The sound changes are not perfect, and are a bit choppy. However, if handled properly, you can get a good sound out of the saber. There are sensitive spots in the hilts range of motion which can make the sound sputter a bit. When you turn the saber off, you get the reverse effect from start up. The blade crawls back into the hilt, and the sound effect that was used in the movie is issued to signify the end of your slice-and-dice spree. As far as accuracy goes, the hilt looks identical to the non working Master Replicas release of the Vader ANH saber. How they managed to keep the cost down and the quality so high is beyond me. This is one super duper cool ass prop. Sorry the picture is so lame. If you want to see some reference pictures of the real MR hilt, check out this link.