The paper investigates the emergence of pair density wave (PDW) states in metallic altern magnets, which are characterized by momentum-dependent spin splitting and zero net magnetization. The authors focus on BCS-type attractive interactions and find that symmetrically distinct PDW states, including Fulde-Ferrell (FF) and Fulde-Ferrell* (FF*) states, can be stabilized depending on the chemical potential. These states break inversion symmetry and exhibit non-reciprocal supercurrents, with the FF state showing non-reciprocal supercurrent in the x direction and the FF* state in both x and y directions. The study uses a microscopic model to derive the Ginzburg–Landau theory and analyze the phase diagram, revealing the conditions under which different PDW states are stabilized. The findings suggest that the supercurrent diode effect can serve as an experimental tool to distinguish between different pair density waves in metallic altern magnets, with potential implications for material candidates such as RuO$_2$ thin films and hole-doped La$_2$CuO$_4$.The paper investigates the emergence of pair density wave (PDW) states in metallic altern magnets, which are characterized by momentum-dependent spin splitting and zero net magnetization. The authors focus on BCS-type attractive interactions and find that symmetrically distinct PDW states, including Fulde-Ferrell (FF) and Fulde-Ferrell* (FF*) states, can be stabilized depending on the chemical potential. These states break inversion symmetry and exhibit non-reciprocal supercurrents, with the FF state showing non-reciprocal supercurrent in the x direction and the FF* state in both x and y directions. The study uses a microscopic model to derive the Ginzburg–Landau theory and analyze the phase diagram, revealing the conditions under which different PDW states are stabilized. The findings suggest that the supercurrent diode effect can serve as an experimental tool to distinguish between different pair density waves in metallic altern magnets, with potential implications for material candidates such as RuO$_2$ thin films and hole-doped La$_2$CuO$_4$.