Click to expand Tap to zoom Caleffi Safety relief valve by Caleffi - Original Spare Part Caleffi Safety Relief Valve for SATK 30/40 HIUs. Quantity Add to Cart This item is a recurring or deferred purchase. By continuing, I agree to the cancellation policy and authorize you to charge my payment method at the prices, frequency and dates listed on this page until my order is fulfilled or I cancel, if permitted.