aftermarket de-ice for Twin Comanche

Hello,

In my continueing search for information on Twin Comanches I've come
across a question on de-ice. I notice some Twin Comaches have it and
others don't.

Is there an after market company that sells the boots,etc? Or were
they all installed at the factory?

Also, what is the difference between de-ice systems certified for known
ice and those that aren't? (I'm not planning to go look for icing,
just curious).

And finally... rough cost of these aftermarket de-ice system?

Thanks!

-dr