This one is one of the weirder, yet creative, licensed Transformers clothing merchandise I've seen.
Three different Transformers shoes/sneakers, that you apparently build yourself!
It doesn't look like there is any reason for it, other than maybe for saving storage space, because it doesn't look like the back of the 'base' is big enough to hold your foot in without the 'legging' bits (unless you wear them like slippers).
Styles are Optimus, Megatron and Bumblebee... and definitely Movie themed.