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Stable voltage until nearly depleted: SR44 silver-oxide cells deliver 4 x 1.55V = 6.2V with a flat discharge curve—almost identical to the original PX27 mercury battery. No gradual drift like with alkaline (LR44) cells.
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Original dimensions without any improvisation: The adapter brings four SR44 cells to exactly 12.7 x 20.5 mm. The battery compartment cover closes cleanly, with stable contact—no tape required.
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Ready to use immediately: Four matching SR44 cells are included with every variant—insert them, screw the cover closed, and keep shooting.
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Affordable standard cells instead of expensive disposable stacks: SR44 (type 357) is a standard button cell, available in packs of 10 for under EUR 5. Replacing the batteries costs around EUR 2—the adapter itself is a one-time purchase.
Compatibility
Suitable for various cameras, including:
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Minox: 35 EL, 35 GL, 35 GT, 35 PE, 35 PL, C, LX [...]
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Rollei: 35 LED, 35SE, 35TE, A110, E110
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Agfa: Optima 335, Optima Sensor Flash
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Hanimex: VEF Zoom
Not suitable for Minox 35 ML, MB, and MBC (these require a PX28 adapter).
Not sure whether the adapter fits your camera? Complete list of all cameras compatible with the PX27 battery type.
What's included
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Standard: 1x PX27 adapter + 4x SR44 batteries
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Set: 1x PX27 adapter + 4x SR44 batteries + 2x ISO labels (replacement)
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Complete: 1x PX27 adapter + 4x SR44 batteries + 2x ISO labels + 1x 30.5mm filter adapter
Technical details
- Adapter material: technical plastic
- Color: Black
- Dimensions: 12.7 mm x 20.5 mm (identical to PX27)
- Battery system: 4x SR44 silver-oxide cells (1.55V per cell, 6.2V total)
- Replaces: PX27 / V27PX / 4SR43 / EPX27
Description
The Minox 35 GT, GL, EL, and PL originally required the PX27 mercury battery with 5.6V—since the mercury ban, there has been no identical replacement. This adapter holds four SR44 silver-oxide cells and brings the stack to the exact original PX27 dimensions of 12.7 mm x 20.5 mm: 6.2V with a flat discharge curve, securely held cells, and a battery compartment cover that closes effortlessly.
The typical workaround—wrapping four button cells in tape and hoping the stack fits—is prone to errors and causes contact problems. In addition to the Minox 35 series, the adapter also fits, among others, the Rollei 35 LED and A110.
Practical tips
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Inserting the batteries: Insert the batteries into the adapter, place the adapter in the battery compartment, and screw the cover closed. The adapter ensures the correct polarity.
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Storage protection: Place the included insulation disc between the adapter and the battery compartment contact when the camera will not be used for an extended period. This prevents self-discharge.
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First roll: Use ISO 400 negative film for the first roll after changing the batteries. Its wide exposure latitude forgives slight deviations while you get a feel for the exposure.
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Easy to restock: SR44 batteries (also known as 357, SB-B9, or SR44W) are available everywhere. You are not dependent on a specialist supplier.
Alternative designations for this battery type: PX27, V27PX, 4SR43, S27PX, PX27S, RPX27S, PX27A, 4LR43, A27PX, 4AG12, U27PX, V7150, Varta 7150, L7150, EPX27, KX27, RPX27, H-4N, MER27, HS3C, 1413MP, 4NR43, VPX27
Want to learn more about battery alternatives for analogue cameras? In our FAQ article about batteries and adapters, we explain all options in detail—including voltage comparisons and recommendations by camera type.
Frequently asked questions
“Do 4x SR44 batteries actually fit in the battery compartment?”
Without an adapter: barely, if at all. Four SR44 cells have a height of 21.6 mm. The PX27 compartment is designed for 20.5 mm—an 1.1 mm difference is enough to prevent the cover from closing. Four LR43 cells, on the other hand, are too short at 16.8 mm and wobble. The adapter compensates for the height difference and provides the correct outer diameter. This exact fit problem is a recurring topic in analogue photography forums.
“6.2V instead of 5.6V—will the exposure still be correct?”
Practical tests and community experience show that the Minox 35 series operates at 6.0–6.2V without any significant exposure deviation in normal daylight. In low-light conditions (dusk, indoors), a slight tendency toward underexposure may occur. If you want to play it safe, reduce the ISO by one stop. Negative film handles this minimal difference without any problems.
“Why SR44 instead of alkaline (LR44)?”
The original PX27 was a mercury battery with 5.6V and an extremely flat discharge curve. The Minox 35's automatic exposure system has no internal voltage regulator—it responds directly to the applied battery voltage. SR44 silver-oxide cells deliver 4 x 1.55V = 6.2V with a similarly flat curve: the voltage remains stable until the cell drops sharply at the end of its service life.
LR44 alkaline cells start at 4 x 1.5V = 6.0V and then decline continuously. Exposure is correct at first, but not after a few weeks. In analogue photography forums, Minox owners regularly report deviations of around one stop when using LR44 cells—without realizing that the battery is the cause.
“Wouldn't 2x CR1/3N lithium batteries be enough?”
2x CR1/3N cells provide 6.0V with a flat discharge curve—on paper, a good alternative. In practice, photographers report CR1/3N cells that already deliver undervoltage from the factory (2.7V instead of 3.0V), particularly from inexpensive suppliers and marketplace counterfeits. SR44 is too inexpensive as a standard watch battery to be worthwhile for counterfeiters, so this risk is eliminated.
“Why not simply buy a ready-made PX27 replacement battery?”
GoldenPower and similar PX27 replacement batteries contain 4x LR43 cells in a plastic housing—alkaline cells with a declining discharge curve and only around half the capacity of an SR44. Cost: EUR 8–15 per battery, for unstable voltage and more frequent replacement. Ready-made 4SR44 or 4LR44 stacks offer no advantage either: EUR 5–7 per stack instead of around EUR 2 for four individual SR44 cells, and they are only available from specialist retailers. For the same price, you get our adapter plus 10 SR44 silver-oxide cells—each with a flat discharge curve and twice the capacity.
