Full details for the 3CX100A5 can be found on the attached data sheet.
It is the same size as the 2C39A with the only visual difference being ceramic replacing the glass.
Ceramic insulation would suggest a higher power than the 2C39A's 20 Watts of up to 2400 MHZ and the data sheet confirms this.
The planar envelope is 32 mm in diameter and, is 69 mm tall.
Absolute Maximum Operating Conditions¶
Updated January 26, 2013.