This sale is for a used but still excellent condition Mamiya C front lens cap, 48mm diameter for most common Mamiya C lenses that take 46mm filters.
This cap has obvious but only normal minor signs of use, and has a chrome Mamiya name on the front. It fits many of the Mamiya C lenses such as the pre-blue spot 80mm f2.8. Try finding another one – these are almost impossible to find.