We don’t normally use measuring cups in the UK but if we did these would be the only 2 I’d own, the Adjustable Measuring Cups.
This patented adjustable measuring cup set is easy to use and measures both liquid and dry ingredients. Simply slide the rubber knob to adjust the capacity to metric or imperial units. Magnets on the bottom allow them to attach to appliances for handy access. Dishwasher safe; disassembles for cleaning. Mini cup holds up to 2 tablespoons. Regular cup holds up to .5 cup.
Available from MoMa store for $33.