Thank you for asking, Karl.
It comes with a 625A alkaline battery. The voltage from a 625A battery is generally close enough for negative film. However, you can calibrate an alkaline battery against a meter of known accuracy, but you may need to do it several times over the life of the battery as it discharges. So, yes, you can calibrate a meter intended for a PX625 battery but using a PX625A battery.
You can buy a "bushing" type battery adapter off ebay and use a smaller MS 76 silver battery. It'll be 1.5 volts, but the discharge is a flat line and it's fairly long lived. So calibrate the meter for 1.5 once with a silver battery and adapter and you're home free.
I bought one of the C.R.I.S adapters years ago that knocked the 1.5v of a silver battery down to 1.35, it sounded great and was around $30. It may have been a fluke, but it lasted a year or two and died. Others may have had better luck, but I wouldn't buy another one for that reason. Too much $$$$ for short life.
I believe I've seen adapters on eBay to use the small 1.4v zinc air hearing aid batteries. Those are super cheap and come in packs of 8 or so from any pharmacy. Probably one of the better workarounds.
The buyer has a number of usable and economic options and can suit him/her self.