Sinclair Sovereign
The Sinclair Sovereign was a high-end calculator introduced by Clive Sinclair's company Sinclair Radionics in 1976 . 
<triplet> Sinclair Sovereign <subj> Sinclair Radionics <obj> manufacturer <subj> 1976 <obj> service entry <triplet> Sinclair Radionics <subj> Clive Sinclair <obj> founded by