Taken from the "kask mojito" description.
"At 220g, the Mojito is no heavy hitter. Thank's to it's light In-moulding construction combined with an expanded polystyrene shell, the Mojito performs excellently in crash situations, helping to prevent injuries".
I've sent an email to Kask.
EDIT: While I await a response, here's the warnings that come with the Mojito Helmet:
WARNING:This helmet is intended for use in athletic activities that are extremely dangerous. FAILURE TO HEED THESE WARNINGS OR FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS INJURY OR DEATH.
WARNING: Please carefully read and understand the following Instructions. Use this helmet for the activities for which it is certified (see Labeling), and those activities only.
WARNING: Improper use of this helmet may cause serious or fatal injury. If the instructions are not followed correctly, the level of protection offered by the helmet can be significantly reduced. Before each use, please carefully inspect the helmet for any signs of visible damage. DO NOT USE THE HELMET IF THERE IS ANY SUSPICION OF ITS CONDITION, ESPECIALLY AFTER A MAJOR IMPACT.
WARNING: It is mandatory that the user is fully aware of all the features of the helmet, its capabilities and limitations, and receives specific instructions and/or training in the proper use of the helmet from a competent and responsible professional.
WARNING: USERS OF THE HELMET ARE FULLY RESPONSIBLE FOR THEIR ACTIONS AND ASSUME ALL RISKS FOR THEIR DECISIONS. KASK, its affiliates, subsidiaries, importers, distributors and dealers will accept no responsibility in the event of any accident leading to injury or even death and will not be liable for any injury, death, loss, or damage resulting from improper use of this helmet.