Panel-mounting, double-sided, Micro BNC connectors (also known as 'back-to-back' or 'bulkhead through-adapter'). They have gold-plated, beryllium-copper, centre contacts for optimum mechanical performance. Connector bodies are gold plated, are insulated from the panel, and have a nickel plated mounting bush.
Panel hole diameter 8.2mm. Body has anti-rotation flat, 7.8mm across body at flat. Suitable castle nut spanner, with 6.35mm hex drive connection, is 55-8197.
Ordering Note: Whilst COAX call these 'Micro BNC', they are interchangeable with the Amphenol 'HD BNC' range (something to do with trademarks we are told!). Please don't blame Canford for the confusion!