LR44 / AG13

LR44 (alkaline) and SR44 (silver oxide) share the same 11.6mm x 5.4mm footprint but behave differently as they drain. The alkaline LR44 has a sloping discharge curve -- voltage falls gradually from around 1.5V toward its cutoff as the cell is used, similar to a car gradually running low on fuel. The silver oxide SR44 instead holds a steady 1.55V for most of its life and then drops off sharply near the end, which makes it far better suited to devices like digital calipers, kitchen scales, and other equipment that assumes a constant supply voltage.

Silver oxide button cells were commercialized in Japan by Maxell in 1976 as a replacement for mercury-oxide cells in watches and other precision electronics, offering roughly double the energy density of an equivalent alkaline cell alongside that flatter voltage profile.

LR44-format cells are sold under a long list of equivalent designations depending on the manufacturer and chemistry, including A76, AG13, L1154, and 357. This proliferation stems from different battery makers historically applying their own part-numbering systems to the same physical size before the size was folded into the IEC's unified LR/SR coding, and it remains a common source of confusion for shoppers trying to match a replacement to an old device.