I don't know what type of iPhone I have?

I don't know whether or not my phone is and iPhone 4 or 4s and it doesn't say it on the back of the phone. How do I find out what it is?

This thread is for those who are going to buy an iPhone 4S through eBay or Craigslist. Since the iPhone 4S didn't get a design upgrade, it is difficult to tell the difference between the iPhone 4 and the iPhone 4S. Its the same way the iPhone 3GS was identical to the iPhone 3G.
I had a similar experience where I bought an iPhone 3G through eBay but I ended up with an iPhone 3GS and so the parts I had were incompatible.

I made a video to help out in case if it helps out.

Please feel free to add anything that I have missed during the video to help others out.

Through iOS5
- The iPhone 4S has Siri which is an exclusive feature only for the iPhone 4S

Through the design
- The iPhone 4S has a model number of: A1387 while the iPhone 4 has a model number of: A1332
- The iPhone 4S has 4 antenna breaks while the iPhone 4 GSM Model has 3.
- So the iPhone 4S MUST NOT have a antenna break on top of the phone and MUST have a antenna break above the vibrate switch and on the top right side of the phone.
- The iPhone 4S has the same antenna band as the iPhone 4 CDMA version but the iPhone 4S has a Micro SIM Card Slot
- So if the iPhone 4S DOES NOT HAVE a Micro SIM Card slot, then its NOT an iPhone 4S

The 4s has Siri. If you don't have Siri, you have a 4. (You service provider can also tell you)

Take a look at this pic, you can tell by that dark line. Cheers.
I don t know what type of iPhone I have - 1

Iphone 4s has siri iPhone 4 has voice control. To find out hold down the home button until Siri or voice control pops up. Siri will say what can i help you with and voice control will say voice control