Energizer Batteries discontinued

Energizer Holdings are the company now owning Eveready (NCC) / UCAR / Ever Ready (UK) / BEREC etc.  Energizer was originally just the brand name for USA Eveready Alkaline batteries. The UK Ever Ready versions were marketed as "Gold Seal".

If you visit the corporate site they do have PDF of specifiications and tables of batteries, but the page links vary and the lists are very incomplete. Also search the part number generally and on Amazon to find if Energizer/Eveready models still are available or an alternate make is available. Known equivalents (same voltage, connector and size) should be added to the relevant model page for the battery.

Check Eveready, Ever Ready and Pertrix / Varta pages. Other historic makes to check for data are Exide / Drydex (UK and USA are not the same!), RCA, Zenith, Siemens (earlier there was a UK company by the brother of the German company founder, so early UK batteries may differ), GEC, Vidor, Oldham, Daimon, Superpila and Mallory. Mallory rebranded to Duracell, originally just Mallory's alkaline brand. 

While there are many batteries especially for radios, actual radio models have used almost every kind of lamp/torch/lantern battery from tiny AAA to large "996" as well as "bell" and other specialist equipment batteries and cells. So all kinds of batteries need to be documented.

Many smaller layer cells (such as 45V for pocket tube sets) are available still as instrument battteries but are unsuited for a radio as they have round alkaline button cells in an rectangular case and cost $20 to $35. Better to assemble your own.