A generic reusable one from the local hospital supply company. Put the equipment in the water and slowly bring it to any boil, reduce heat to just bubbling for 10 minutes, turn off the water and let it cool.
Disposable nebulizers meant for one time or single patient use cannot be boiled- that's why I buy from medical supplier and not Amazon or ebay. If you don't have a local supplier try nebology.com o just nebulizer- you can call and ask them which can be boiled.