- HCD Research Limited, designers and manufacturers of precision reference crystal oscillators and associated frequency control and measurement devices.www.hcdresearch.co.uk
- Quartz Crystal, Oscillator and Filter Manufacturer - Precision Devices UK Limited ...www.hy-q.co.uk
- Manufacturer of Oscillators ...www.onspec.co.uk
- Magna Frequency Components ...www.magnafrequency.com
