Batteries and Things sells the CR1616 3 Volt Lithium Button cell battery.  This one can be harder to find unless you go to a specialty battery store,  where you will in most cases pay a higher price for an ODD battery.  This is a very common one to us here at Batteries and Things.  This battery has a 3-4 year shelf life so why not grab one or two extra for your application.  This battery typically is used in keyless entry remotes, light up dog collars, flameless tea lights, along with watches and other gadgets.

Type: 3 Volt Lithium Coin Cell

Part Number:CR1616

Voltage: 3 Volts

Diameter:16mm

Height:1.62mm

Also know as:DL1616,

ECR1616,

BR1616,

280-209,

DL1616B,

BR1616-1W,

CR1616-1W,

KCR1616,

LM1616,

5021LC,

L11,

L28,

YA.