Harken doesn't make these anymore but spare parts are still available.
New magic boxes of similar quality are nearly $200.00
I've got a used one that I've decided to part with. The line inside needs replacing but that's a quick inexpensive fix.
http://us.ebid.net/for-sale/harken-m...d-64284448.htm
I'll be going through the garage and sailboat the next few weeks to clear out all the clutter. Look for more sailboat parts in the future.