The FM4000's design is inspired by the MVP2500 and MVP4000 cages, which are known for offering the absolute best vision and deflective properties. This single bar facemask features a strong vertical center bar right in the front/center of the mask, positioned in such a way to make it virtually invisible when worn. The curved forehead allows for more padding to come in contact with the umpire's head to help disperse impacts. The steel wire used to make this mask is hollow.
All-Star FM4000UMP System 7 Lightweight MVP Umpire Mask Black
In baseball, why do some catchers wear what looks like a tinted visor at the top of their mask? - Quora
Two-piece vs hockey style helmets - The Baseball Catcher
Catchers are the latest to benefit from the new era in protection with the Force3 Defender mask - ESPN
How do you guys feel about Reese McGuire's red catcher's mask? : r/redsox
Umpire's Equipment Buying Guide
Top 7 Catcher's Helmets
Force3 Traditional Defender Mask – Baseball 360
Catcher's Helmets & Masks - Catcher's Gear