Spherical markers are plastic spheres with a precisely centric M3 threaded insert, which are hand-coated with a highly retro-reflective film.

Available sizes:

Size [mm]	~Size [1/64 in]	Used in standard targets:
12	30.2	Hand, Shutter glasses, Passive glasses
14	35.3	Flystick2, Elbows
16	40.3	Foot
20	50.4	Tree, Calibration Tool
30	75.6	Calibration angle (large)

Flat markers are precut circular pieces of self-adhesive retro-reflective film.

Available sizes:

Size [mm]	~Size [1/64 in]
10	25.2
12,5	31.5
15	37.8
20	50.4