Plain talk about battery adapters found!
I copied the following off a US online store website--brought to you as a "public service." The text refers only to a MR-9 Kanto/ C.R.I.S. adapter and 386 battery, but the principles are the same for all such adapters and silver oxide batteries.
MR-9 Adapter FAQ
Q: Can my camera or light meter be modified for cheaper, alternative batteries?
A: Yes, however modification costs usually run two to three times that of the MR-9 adapter. In many cases modifications are not linear or accurate at all light levels.
Q: My product requires two PX-13 batteries. Do I need to order two MR-9 adapters?
A: Yes. Order one MR-9 for each PX-13 battery needed.
Q: Is the MR-9 Adapter reusable?
A: Yes, the adapter should be a one time purchase. There are no moving parts and the input voltage of the 386 battery will not harm any of the circuit components. Remember to change only the 386 battery when exhausted, not the entire adapter.
Q: Are there any photo products that the MR-9 adapter will not fit or work with?
A: Perhaps, although we have not found any. The MR-9 works with photo products that originally required the use of the PX-625 or PX-13 mercury batteries
Q: When the silver 76 battery is installed in the adapter, is it exactly the same size as the PX-625?
A: No, it is slightly thicker by approximately .010". In some cases this only means the battery cap may not screw in quite as deeply as before.
Q: My light meter reads incorrectly with a new alkaline cell. I have to adjust the ISO/ASA to compensate, but even after doing this some light levels read incorrectly. Will this happen with the MR-9 adapter?
A: No. This is precisely why the MR-9 adapter was developed. When you install the MR-9 adapter with the silver oxide 386 battery in your camera the meter should be accurate at all light levels.
Q: What is the voltage fall off, or discharge curve with the silver 386 battery?
A: Silver batteries have a different discharge curve than an alkaline, and they also produce more current. This makes them ideal for use with cameras and meters that use the PX-13 because of their low current consumption.
Q: How long will the 386 battery last in my camera or light meter when used with the MR-9 adapter?
A: It is difficult to answer this question, as the life will vary according to use and type of product. We recommend that the 386 battery be changed once a year, even though it may last much longer.
Q: Is there any maintenance or special storage requirement for the MR-9 adapter?
A: No. There are no special requirements.