Check the listing for details. Danner Pondmaster Replacement Impeller Assembly 190 gph pump Model MD1.9 12955. Condition: New. Listed at 15.99 USD. Danner Replacement Impeller Assembly Model #12955 Replacement impeller assembly for MD1.9. MD1.9 is a 190 gph Pondmaster Magnetic Drive pump. To replace on a Pondmaster pump, first unplug the pump. Remove the 4 screws holding the outflow cover. Remove the cover. Simply remove/replace the impeller with your fingers. Reinstall pump cover and test. We will not allow returns/refunds if the impeller has been opened! Sorry. We will combine shipping whenever possible. If you would like to know the shipping charges before paying for your combined order, please choose the "Request Invoice" option during checkout (or "Commit To Buy" without actually paying). Shoot us an email if you need assistance. Thanks for visiting my store. We are here to help you with all of your gardening needs. Please email us with any questions or concerns.