Denali Auxiliary Light Mount for Forks – 39-49mm This DENALI Fork Tube Light Mount Kit allows fitment of most Auxiliary lights to conventional forks, or any tube 39mm - 49mm (1.5-1.8in) in diameter. These light mounts have a unique octagonal inner profile that allows the clamps to securely grip a wide range of tube diameters and include an optional, fully rotatable mounting shelf to create a super versatile and robust light mounting solution.