This is a treble booster based on the original Dallas Rangemaster, the secret ingredient for the legendary sounds heard by Eric Clapton in John Mayall's Bluesbreakers, Rory Gallagher, Brian May and Tony Iommi along with so many more! Available at JetCityMusic.com.
http://www.jetcitymusic.com/index.php?page=shop.product_details&flypage=vmj_naru.tpl&product_id=473&category_id=31&manufacturer_id=32&option=com_virtuemart&Itemid=89