Customized base mount for those helmets that have a vent down the center, making a typical action camera mount impossible to use. This spans that gap. Helmets that we know work well with this mount are: Bell 4Forty MIPS Bell Drifter MIPS Bell Formula Bell Nomad 2 MIPS Bell Sidetrack II Bell Sixer Bell Super Air R Bell Super Air Spherical Bell Super DH Bell Z20 Bontrager Blaze WaveCel Mountain Bontrager Circuit WaveCel Road Bontrager Quantum MIPS Bontrager Ralley WaveCel Mountain Bontrager Solstice MIPS Bontrager Specter WaveCel Bontrager Starvos WaveCel Round Fit Bontrager Velocis MIPS Road Bontrager XXX WaveCel Road Giro Cinder MIPS Giro Ember MIPS Giro Fixture MIPS Giro Hale MIPS Giro Helios Spherical Giro Hex Giro Montaro MIPS II Giro Radix MIPS Giro Register MIPS Giro Source MIPS Giro Switchblade MIPS Giro Trella MIPS Giro Vasona MIPS Giro Verce MIPS iXS Trail Evo iXS Trail XC iXS Trigger AM Kali Alchemy Kali Cascade Kali Invader Kali Lunati Kali Uno Kask Caipi Lazer Coyote MIPS Lazer Impala MIPS Lazer Z1 MIPS POC Axion POC Kortal POC Octal POC Tectal POC Ventral Smith Convoy Smith Network Smith Persist Smith Signal Smith Trace Specialized Prevail 2 Specialized Prevail 3 Specialized Prospero III