Depending upon the product range, bell push batteries required are either of the 'stubby' Alkaline type for the DBxxx and Bxxx ranges, or of the coin cell type for the BYxxx and DBYxxx range, as illustrated below;
DBxxx and Bxxx ranges
Types known as - A23/MN21/LRV08 depending on the manufacturer's own code, are all 12v and compatible. They are usually available to obtain singular or as a twin pack.
TIP: Do not use the LR1 type however as though physically similar it is only 1.5v and not compatible!
This type is known as a CR2032/DL2032 Lithium coin cell . These are available singular, as a twin pack or as part of a multi-card pack.
TIP: There are several similar coin cell batteries and all of which are 3v, however they differ in their thickness. As such only the CR2032/DL2032 has the correct thickness compatible with the BY bell push
The 'DBY' range uses two types of battery dependent on product one being the CR2032/DL2032 the other being a CR2450. Much like the CR2032 the CR2450 is a lithium coin cell that is available both singular, twin pack and as a multi pack.