White’s C-Cell Battery Holder fits the XL Pro / SL Series; the 6000SL, 5900SL, 4900SL, and TM808 machines. Holds 4 “C” size non-rechargeable batteries. Can also be used with rechargeable “C” size which requires their own charging system. Used in mid-range and top-of-the-line models from 1983 to date. Internal contacts should be scraped clean regularly.