I use a similar digital timer from RS Components, cheaper than Transair and it has 3 separate timers so you can keep total time and time on leg separately.
Bolt a scrap of sheet material through the stopwatch holder hole on your kneeboard and stick it on with sticky velcro.
It comes with a spring clip (easily removable) and it also has a magnet on the back which I have removed to prevent it interfering with the compass.
Parsimonious Mike