Hacker Battery retainers
 

Where these round retainers are fitted e.g. RP25, I always find them missing leaving two ugly circular stains. This was the case with my latest RP25 restoration and a quick visit to the Pharmacy literally next door came up with the pictured Callus Cushions. These are by ProFoot and are 50% larger than other brands. Easy to fit and by the way, your batteries should never get calluses :D :D