Silicone tip brushes.
A great tool for any modeling job.
The white limbs are of normal hardness and the black ones are of slightly higher hardness.
Suitable for modeling putty, Apoxie Sculpt, Greenpower, Milliput, Sculpey, Fimo, etc.
Use water, alcohol or petroleum jelly as a softener to prevent the putty from sticking to the tip of the brush, prolong its life, and regularly wash them gently with soap and water.