Detachable

• The Nordic Skater
  
  Detachable ice and roller skates that clip onto boots with a quick-release binding, and safety equipment for ice skaters. ...
  http://www.nordicskater.com/

• PedalPro (Circle Mountain Industries,Inc)
  
  Detachable pedal propeller drive unit that fits small boats such as square stern canoes and row boats. ...
  http://www.pedalpro.com/

• AirCoast
  
  Designed with structural suspension. Rugged enough to take on the streets with its big assuring wheels. With detachable wheels so that you can roller skate, run it like a training shoe, or climb the mountains with the wheels off! ...
  http://www.aircoast.com/

• Hypno Skates
  
  Hypno detachable blade skates. These inline skates allow the wearer to skate on regular inline skates and quickly convert the skates into regular footwear. ...
  http://www.hypnoskates.com/