The C1242-1530 Conical Marking Discs for Follow Focus Unit, 10 Pack from Oconnor are replaceable cone shaped marking discs for the knobs of select follow focus units. The discs snap onto the knob, and you can use non-permanent type markers such as wet or dry erase for your focus marks. The angled surface makes it easier to view focus marks when the focus puller is off to the side of the camera, or when the camera operator is the one pulling focus off of the focus marks.
The ten pack provides you spares, so if a marker disc requires extra cleaning time, you have a replacement ready to go. The marker discs are designed to work with an available Oconnor Hard Stop Handwheel, however they are also compatible with available Arri MFF-2 and LFF-1 follow focus knobs.