The two-pack Marking Disk Set from PDMOVIE is designed to work seamlessly with the PD4-HT Controller of the REMOTE AIR PRO 3 focus motor system. Crafted from durable white plastic, these disks enable the creation of personalized focus marks for precision focus adjustments. With two disks included, you can conveniently pre-allocate each one to correspond with the focus scales of different lenses, allowing for quick swaps between lenses or maintaining a pristine spare for use whenever necessary.