Be wary of them depending on the manufacturer. Picked up pair from Spirit Halloween two years ago and the part in front that looks like three pieces actually came apart within the first hour of wearing them. Luckily I was able to get a refund. There are four companies that make them, avoid the ones from Hong Kong, but the other three are pretty decent. If the one you have pictured are the ones made in the U.K. then they are good to go.
To everyone asking about where to get them you can find them on ebay and Amazon fairly easily. The most common name for them are Horror Walker, Space Walker, and Terror Walker since they are modeled after Anakin's boots in RotS.