About the SR927W Battery
SR927W is the name of a small 1.55 volt silver oxide battery used for small electronics.
The S stands for its silver-oxide positive electrode terminal.
The R stands for its round shape.
The 927 stands for 9.4 mm diameter, 2.6 mm height.
The W means the battery meets the International Electrotechnical Commission (IEC) standard for watch batteries.
The SR927W batteries are made with several other common names. Silver oxide name variations include SR927, SR927SW, SG7, 395, 399. Alkaline variations include AG7, 195, LR927.
Silver Oxide vs Alkaline
Often times you will see online stores selling alkaline batteries AG7 as compatible SR927W batteries. Usually, there is no problem for those batteries to work, but they will not last as long and die quicker. Silver oxide batteries made by Maxell, Energizer, etc have larger capacity. Silver oxide batteries also have more stable voltage until the battery dies. Alkaline versions slowly drop in voltage as they die. A device that requires a high voltage should use silver oxide cells.