Brake and gear cables are traditionally attached to bicycle frames with lugs on the outside of the tubing, this is known as external routing.
Recent advances in technology have allowed manufacturers to route the cables through the inside of the tubing, this is known as internal routing. Internal routing gives a very clean appearance, can increase the stiffness of the frame due to additional channels and in some cases may provide aerodynamic benefits too.
For certain applications, including full suspension bikes and cyclocross bikes, manufacturers use an outer cable along the full length of the cable to protect the inners from mud, water or accidental damage, this is known as full outer.
Bicycle wheels come in a wide range of sizes from 12" wheels found on smaller Kids Bikes to larger 29" Mountain Bike and 700c Road Bike wheels. Larger wheels are normally faster and more stable at speed and their larger contact patch improves grip too. Smaller wheels are normally lighter, more maneuverable and have quicker acceleration.
Wheel sizes are defined by the country that first popularized the style of bike that used them - so you'll see some imperial and some metric measurements listed. Wiggle includes the ISO standard in brackets after each for ease of comparison.