Doesn't suit? No problem! You can return within 30 days
You won't go wrong with a gift voucher. The gift recipient can choose anything from our offer.
30-day return policy
The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle s