These battery extenders come in two lengths. 6.5" for two D cells and a C cell and 8.8" for a 3 D cell and a C cell. These are made of grade 9 Titanium with a OD of 1.5", a ID of 1.36 approximately and a wall thickness of .070. These will not give you more battery life but extend your maglite for a good ass whooping stick. The use of extra battery's may diminish the life of the bulb in the maglite. SDTA is not responsible for the wear of your light bulbs. (This extender will include the Maglite Battery adapter also starting 9/29/2017).