The UIDevice class provides all the information of the device on which your app is running.
UIDevice *deviceInfo = [UIDevice currentDevice]; 
NSLog(@“OS running on device: %@”, deviceInfo.systemName);
// OS running on device: iPhone OS
    NSLog(@“OS Version running on device:  %@”, deviceInfo.systemVersion);
  //OS Version running on device:  7.1
    NSLog(@“Device model:  %@”, deviceInfo.model);
  // Device model:  iPod touch  
size_t size;  
sysctlbyname("hw.machine", NULL, &size, NULL, 0);  
char *machine = malloc(size);  
sysctlbyname("hw.machine", machine, &size, NULL, 0);  
NSString *deviceModelVersion = [NSString stringWithCString:machine    encoding:NSUTF8StringEncoding];  
free(machine);  
NSLog(@"Device model version: %@", deviceModelVersion);  
//Device model version: iPhone4, 1  
NSLog(@“Device name:  %@”, deviceInfo.name); 
//Device name:  my iPod