HS1 Jockey Skull. The Gatehouse HS1. SNELL E2001 is the highest manufacturer Equestrian Hat safety standard in the world and includes a unique test that simulates a rider falling into a fence rail, or having a secondary hit by a horse's hoof. It features a top quality leather four point harness and the Gatehouse Airflow lining. This hat also comes with a free padded storage bag. Suitable for competition under FEI, Pony Club and HRA rules.