What do 'UM' and 'WM' in the stamp sections mean?
UM=unmounted rubber stamp. My definition of unmounted is a stamp without cushion or wood--just the rubber. If I have it, I will include a piece of paper with the picture on it. Unmounted stamps save you money, save you storage space, and allow a wide range of mounting systems. My favorite is HALOS (Hooked And Looped On Stamps).
WM=wood-mounted stamp. This is what you normally see in the craft stores. Yes, it's easy to use, but eventually your stamp area will have no more room for them.