A little history of Walter and these great amps.....back in the 1980's I bought one from Walter Woods direct from the USA, they were expensive for the time but... double bass player Rufus Reid was playing one at Ronnie Scotts with the mighty saxophonist Dexter Gordon. I asked during a break what 'that little red box was' that was powering two Bose cabinets, (the ones used in PA systems). It was a WW 100 watt amp. He convinced me, a budding double bass player, to get one. I called Walter to order and asked how he made such a small amplifier and he explained that when the USA government started releasing previously held information from the public, he went to the N.A.S.A. info 'pages' to find out how a space craft could send a coherent voice signal from the moon to Earth and he nabbed the technology for his amps and so made possibly the first digital commercial amplifiers..
Good luck with the sale robbuu, the amp looks to be in great shape.