They are 'Stopanynastythingsgoingintotheengines' kit. The Dyson vacuum cleaner also uses the same principle. The front has a plug that can be opened or closed, and on the side are the FOD/ice seperators. These are small tubes with a spiral in them that spins the air so that anything solid is ejected out of the side and only clean air goes in the intake. A very good idea especially where there is a lot of abrasive dust around.
Some foreign Pumas have a system where the plug is opened when the undercarriage is raised so that the engine receives pitot or ram air.