Each module snaps into the socket magnetically, and its fool proof to insert/remove each piece. Really like these. The block pattern on the sole also fits into the pedals of my hybrid bike perfectly - grip is so secure it almost feels like I?ve got cages on the pedals. It feels like you?re walking on sharp glass. , but so far Im impressed. I wouldnt sleep on it directly it is not that nice on the skin. too small and then I had to pay over $3. After digging into some customer reviews I discovered this is a MONO speaker and that single speaker is on the right instead of the center. First, they are comfortable. Being assigned to a Violent Crimes Task Force in an urban city, I have pushed these shoes to their breaking point.