Based on this product's specifications, here are some alternatives and similar models
Lithium Thionyl Chloride Battery SATEL BAT-ER34615 3.6 V ER34615M (AA-size D-cell format)
Summary description:
Replacement lithium thionyl chloride battery SATEL BAT-ER34615 (ER34615M) with nominal voltage 3.6 V, designed for long-term primary power in metering, alarm systems, memory backup and industrial electronics. Offers low self-discharge and wide operating temperature range typical for Li-SOCl2 chemistry, suitable for devices requiring stable, long-life primary cells.