Schlegel Operators Devices, RONTRON Q-JUWEL Series Catalog (PDF-18Pg) Flush-mounted control units and pilot lights for 22.5mm mounting diameter. They are flat enough (1.4mm) and are a good alternative for membrane keyboards. Front bezels are flat and rounded square shape. 22mm mount with rounded square shaped bezel. Suitable Contact Blocks DMF SERIES Features: Transmitter module for wireless push button Energy input E-Pulse External Antenna required B-SERIES Features: 3mm travel Lamp socket T5.5K (telephone slide base) or W2x4.6d (wedge base) Connection = Fast-on terminals 2.8x0.8mm or PCB mount terminals or screw connections C/P-SERIES Features: 3mm travel Lamp socket T5.5K (telephone slide base) Connection = PCB mount terminals