*PLUMBERSSTOCK EXPERT* responded:
Thank you for seeking answers from PlumbersStock.com! Yes, you may use this K-Rain P8003050 stem/disk assembly in a 4-zone system provided that the indexing valve used belongs to the 6000 series. Please see page 9 of this K-Rain 6000 Instruction Manual for reference. The model number of your valve, also known as the product number, can be found on the box or product label, or on its manual. Please provide us the exact product number of your valve so we can better assist you. Thank you for visiting PlumbersStock.com!