A Charles Owen J3 Jockey Skull, the same model that was worn by Darren Chiacchia for cross-country.
The 42-year-old was critically injured in a cross-country fall in Florida on March 15, and has been in intensive care at Tallahassee Memorial Hospital since.
Darren is among dozens of top-level riders in several disciplines who wear and endorse Charles Owen helmets. He was wearing a J3 Jockey Skull in the cross-country. His family said "it is abundantly clear that Darren's fate would have been far worse if not wearing a quality helmet".
"The Charles Owen company ... has been a generous sponsor of Darren and a huge part of the current campaign to assist in paying Darren's medical expenses."
Darren is still gradually improving, they said. He is responding to voice commands and moving his extremities with more consistency.
There are still problems with his left lung, which is still being drained via a chest tube.
"Cognitively he is more alert, and able to indentify familiar faces. The hospital staff is pleased with his progress," they said.
• Surveys in the UK and the US earlier this year by IPC Media revealed that more riders choose to wear a Charles Owen helmet than any other brand. The results were provided by a nationwide survey compiled from readers of the magazines Eventing, Horse and Hound and Horse, according to Charles Owen and Company.
Horse and Hound has a weekly readership of 257,000, and the survey showed that for the second year running 60% of its readers wear a Charles Owen helmet.
The monthly magazine Eventing has a circulation of 12,000, and 67% of eventing readers said they own a Charles Owen helmet. Readers of the monthly magazine Horse, with a circulation of 22,241, found that 50% of readers used a Charles Owen hat.
Roy Burek, Managing Director of Charles Owen and Company, said: "We are starting to understand the long term effects of mild head injuries and medics are starting to question the desirability of helmets designed on steel heads in test labs that are too strong.
"Our passion for safety and quality continues to drive the company forward, manufacturing our handmade, British hats to highest of standards, with the simple aim of saving lives."