crash helmet 
noun
A helmet worn by a motorcyclist to protect the head in case of a crash.Neither were wearing protective clothing or crash helmets....
- Its 200 highly trained members dress in white overalls, padded clothing and crash helmets to protect themselves against police batons and shields.
- Some advise wearing a motorcycle crash helmet with full-face visor, others say ski goggles work fine.
- inactivate
- inactivation
- inactivator
- inactive
- inactively
- inactivity
- in actual fact
- in addition
- in a delicate condition
- inadequacy
- inadequate
- inadequately
- inadmissibility
- inadmissible
- inadmissibly
- in advance
- in advance of
- inadvertence
- inadvertency
- inadvertent
- inadvertently
- inadvisability
- inadvisable
- in a fair way to do something
- in a heap