You mean porous materials? Something that's porous can hold on to bacteria and can't properly be fully sterilized. Sharing is discouraged on porous materials since it could cause infection or worse. Always use a condom if you're sharing with someone else or with more than one orifice.

Non-porous materials are always safest since they can be fully sterilized by being beached, boiled, etc.

Let me know if this answered your questions or if I misunderstood the answer you were looking for.

thank you ladies that is exatly what i was looking for. i thought it had micro holes. i jsut wanted to be better educated on it.