This is a 3.65V Lithium rechargeable battery.
I used this li-ion cell to replace both ni-cad batteries in my old Wahl micro portibile soldering
iron. the resultant 3.6 volts worked perfectly with the old 2.8 volts conbined ni-cads.
Also the 4Ah rating gives me twice the time per charge as the old batts.
The size of the single cell is just a little shorter than the 2 sub c nicads,
otherwise all other diminsions fit perfectly.
Good product .