Simple Interval Timer (SIT) can be used for any kind of interval training, such as running, cycling, HIIT sessions (including Tabata method), stretching, etc.
SIT Watch runs independently of the phone, so no need to have your phone around during your workouts (although you will need your phone during the very first time you launch SIT watch).
SIT Watch features the same simplicity as the iOS app while offering the same functionality, plus it will measure your heartbeat during the workout sessions.
On the iOS an extra switch control allows you to prevent the screen from dimming.
Swipe left across the Settings screen to switch to another configuration.
It features a nice plain design, with no unnecessary controls.
SIT can run in the background, while you are playing music, watching videos or doing anything else on your iOS device.
An interval timer, which is easy to set up and use.
The recordings will be available in the Apple's Health app.
SIT remembers the last 5 configurations you have used.
SIT is exactly what you would expect.