Comparison of the rotation period distribution of NGC 2281 (black) with other open clusters of relevant age. Left: NGC 3532 (orange, 300 Myr, Fritzewski et al. 2021b) and Praesepe (blue, 670 Myr, Douglas et al. 2019) bracket the previous age estimates. From the rotation periods it immediately follows that NGC 2281 is younger than Praesepe and older than NGC 3532, although perhaps closer in age to NGC 3532 than to Praesepe. Right: M 37 (green, 450 Myr, Hartman et al. 2009) and M 48 (pink, 420 Myr, Barnes et al. 2015) have nearly identical rotation period distributions to that of NGC 2281 (black), including the faster rotating stars. This suggests similar ages for M 37, M 48 and NGC 2281.