One-body type water- and air-cooling fixed masks made of forged 0.2% beryllium copper alloy have been developed, and successfully applied for the front end of a new undulator beamline, BL-13A, at the Photon Factory in Tsukuba, Japan. Advantages of the masks are a simple structure, no welding, low cost, high duration, and an extremely low out-gassing rate. Forged 0.2% beryllium copper alloy is demonstrated to be a valuable material for synchrotron radiation instruments.