British Pedal Co. Dallas Rangemaster Treble Booster

They say:

This is a detailed replica of one of the worlds most iconic effects. The Dallas Rangemaster ® treble booster, originally produced in 1965 has been used to by many of the worlds most respected artists including Eric Clapton, Tony Iommi , Rory Gallgher, Brian May, Marc Bolan, Richie Blackmore and many more… although classed as a Treble Booster the Rangemaster ® was used as an overdrive pedal to give a more distorted but focused tone with many classic British amplifiers that included the legendary Marshall Bluesbreaker and Vox AC30