Light grey ABS discs.
These ABS plastic discs can be used as wheels or detail on scale models, architectural models, engineering and radio control models.
ABS offers good impact strength and can be glued to itself with a methane based cement such as Plastic Weld.
When gluing to wood use a good quality PVA, a medium viscosity superglue is good for most other purposes.
Cut with a fine cut razor saw.
To paint, first wash & dry the disc, lightly sand with a medium sandpaper (Flexisanders are good), then use a plastic primer. Finish with an acrylic spray.