Leofoto CFC-01 Lens Collar
"The Leofoto CFC-01 Lens foot/collar has more functionality than the stock foot collar that comes with the Canon RF 100-500 lens. It has a built-in Arca Swiss machined groove so you don't have to bolt on an additional arca Swiss plate. . . The foot is also longer than the stock Canon foot so it's easier to use it as a carry handle. . . It actually fits better and rotates on the lens better than the stock collar. . . It also has a receptacle hole that can be used with a Leofoto SP-01 Quick Release Strap mechanism. . . I will keep the stock Canon collar/ lens foot in a box if the lens is ever sold but the Leofoto version is far better and will be used full time with the lens."