The HH9954 is the only Von Duprin hurricane impact-rated mullion.
Hurricane ratings vary by location and application.
Be sure to check with the local authority and/or the Regional Allegio...
The Von Duprin 4754, 4854, 9954, and 9854 mullions can be converted or ordered with key removable option.
KR54-F kit is the conversion kit to convert the above mullions to key removable mullion.