Part # ASC-003A. AT cut, .550" diameter, plano/convex replacement QCM sensor. Alleviates stress that occurs during multi-layer & harsh material coating, leading to more stable performance. Works with Inficon, Maxtek, Sigma, Satis, Edwards, and Intellemetrics. Sold in discs of 10. Direct replacement for FilTech's QI8008, only less costly.