The Valve Spring is used inside the solenoid supply valves on the XT10/XT10I, XT15/XT15I, HCl/HClI, DELTA/DELTAI, A2000/A2000I, and TDF/TDFI instruments and is inserted inside the Valve Piston w/ Viton® Seal. 

Note: For XT10/XT10I and XT15/XT15I - This spring cannot be used in valve Q5. For replacing the Q5 Valve Spring, order Part #: X35.