Just to add to what David said about fin sizes... to add a little confusion to the foot pockets not always being exactly the sizes they claim to be, some manufacturers will mark sizes in 2 different ways. The pair of Mares fins I'm currently using says "40-41" as well as "6 1/2 - 7 1/2", which are not really the same size range based on the chart posted. Use the size you think you are as a starting point and don't be surprised if you end up a couple of sizes bigger or smaller than that.
