Super Comfort Liner Upgrade size Large for a HGU-56/P Helicopter Helmet. It is brand new in the bag, never opened. If you have any questions please let me know. Here is some information I found on the Gibson & Barnes website which sells this item for $108 + about $20 for shipping:

HGU-56 Super Comfort Liner (SCL)

A superior custom fitting helmet product, the Super Comfort Liner (SCL™) provides the protective benefits of Gentex's Thermo Plastic Liner (TPL®), and offers enhanced comfort. The SCL cover provides a more plush visco-elastic foam padding compared to the TPL cover, but still offers maximum helmet retention during aircraft maneuvering, acceleration and long-duration missions.

The SCL has two features that make it a very comfortable liner; the visco-elastic foam in the cover and the Thermoplastic layers of the liner. The visco-elastic foam’s temperature softening properties allow the cover to conform to individual shapes when in contact with a warm surface, distributing weight evenly while reducing pressure points and "hot spots." on your head. The thermoplastic layers above the cover are molded to create dimples, which partially collapse to conform to your head due to the heat from your head. These layers also contribute to the impact protection of the helmet.

The SCL is lined with a removable and washable liner that is attached with hook-and-pile fastening tape to the Energy Absorbing (EA) liner.

These unique and flight-proven qualities ensure increased stability while nearly eliminating the need for additional custom-fitting procedures.

The SCL liner is an upgrade to the TPL liner.