WMR-cards have face-values of 500, 1000, 3000 and 5000 WMR (equal to RUR - Russian Rouble). They can be used to add funds to user R-purses and also as digital WMR cheques for payments in the Paymer system.
WMU-cards have face-values of 50, 100, 200 and 500 WMU (equal to UAH - Ukrainian hryvnia). They can be used to add funds to user U-purses and also as digital WMU cheques for payments in the Paymer system.
You can view previous designs and serial numbers of WM cards here