The optimal ranges of L_op ± 1σ to identify the observed QPO frequencies with the crustal torsional oscillations, shown for various NS models. The gray shaded regions denote the range of fiducial value of L, i.e., L = 60 ± 20 MeV in light gray (M. B. Tsang et al. 2012; W. G. Newton et al. 2014; B.-A. Li et al. 2019), and the range of L constrained from the identification of magnetar QPOs observed in SGR 1806-20 with crustal torsional oscillations, i.e., L = 58–73 MeV in dark gray (H. Sotani et al. 2018; H. Sotani 2024).