BT-16 Battery Case for TH-K20E Discontinued model Key Features Dry-cell case for the TH-K20A/E and TH-K40A/E Amateur transceivers Takes 6 x AAA (LR03) Alkaline batteries Battery Cases BT-14Battery Case - 6 x AA CellsBT-13Battery Case - 4 x AA CellsKBP-6Dry Cell case - AA cells (Red colour)KBP-5Dry Cell case - 6 x AA cells