I assume you mean treadmill(?). A treadmill is a stationary exercise machine on which you can run or walk for exercise. If you go into almost any gym you will see them. They are great for cardio exercising especially in the winter when conditions are bad outside.
Set the speed at 7 mph
Yes, it is. Running on a treadmill will certainly help, but treadmills don't have the incline variability of natural terrain, so your body won't be prepared to run the half-marathon. Training on a treamill is a great way to prepare for a mini marathon. It would also be a good idea to get some actual track time in if possible.
There are many features of the Sole e35 treadmill. The Sole e35 treadmill has 16 levels of resistance, a message window with blue backlighting and a pulse readout. The treamill also comes with water bottle/accessory holders and a residential warranty.