(!!!) (Single) 6100=CV4058=6C4 Mullard box plate NOS 1973 (9ma)
(!) (Best Single) 6100=6C4WA GE Corvair black plate triple mica 1964 (10.4ma)
(Best Single) EC90=6C4 Mullard branded Philips UK box plate NOS 1967 (11ma)
