The Vacuum Products Group of MKS Instruments has published a revised and expanded catalog for the HPST series 23 ButtWeld fittings. The catalog now has a parts listing and includes new products, tips on welding practices, technical drawing dimensions and prices. The components are designed to be used in conjunction with the full line of HPST CF, ISO-Universal, and ISO-KF flanges, for easy welding during on-site installations.