http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=121232830034 those are what I bought for my two torches. However coming from the old reclaimed laptop ones I was using these were a marked improvement. More to do with output I could run both my torches on medium and get at least 3hrs runtime with really good output on the Cree XML T6 LEDs. To be honest on the 502b torches the diff between medium and full wack, is not huge but runtime is useless.