Bell, Z20 Bell, Z20 from Hilgard Muller Bell, Z20 The most advanced road cycling helmet on the market. I have multiple patents on the technologies that are incorporated into the Bell Z20 gLike Bell, Z20 The most advanced road cycling helmet on the market. I have multiple patents on the technologies that are incorporated into the Bell Z20 3D Modeling Industrial Design Bicycle Product Development Product Design Sketchbook Pro Outdoor Equipment Share R 7 n Hilgard Muller Sr. Industrial Design Professional Chico, CA Follow Contact