E288CC MULLARD HEERLEN OLD SHIELD WHITE PRINT 8223 NEW WHITE BOX
The E288CC, 8223, tube is a variant similar to 7308 and 6922 tubes. They have filament current that is higher than 6922 tube types but in most circuits it is not substantial enough to be a concern. The envelope is approximately 1/2 inch taller which is also a consideration where it is to be used.