Update, I added another picture of the capsule as I was getting asked if it was reskinned because it was so clean. It is original. The original two pictures do not show the little dust that is there so I took another that shows more detail.
Also reach out if you want to hear some audio files recorded from it.

AKG 414 EB Brass CK12 capsule with AKG SA18 Mic Clip
I have 3 of these and am letting this one go. The other 2 are super close in serial number so keeping that pair for now. 
This one is in excellent condition and everything functions as it should. It sounds amazing. Sounded great on Freddie. 
I just used it on a section of a great choir recording and then the lead vocalist also.
It has the sought after brass capsule which of course is in C12, C24 and 251 microphones.
As you can see it is a very very clean specimen, especially being this one is an older serial number. 
The clips themselves are selling for about $150.
Feel free to reach out with any questions.
I have great feedback on Reverb and Ebay. Can show or pickup in person in Minneapolis at Winterland Studios.

The AKG C 414 EB is an excellent all-purpose condenser microphone that really shines on vocals and acoustic instruments, but works well on almost anything. Based on its predecessor, the C 414, the C 414 EB incorporates the revered CK12 capsule with solid state amp circuit. Like the original C 414, the EB provides four polar patterns - cardioid, omnidirectional, figure-of-8, and hypercardioid - selectable via a switch below the capsule on the front of the microphone body. The C 414 EB features a left-side switch that controls the pad with settings of 0 dB, -10 dB, and -20 dB. The right-side switch controls the HPF with flat, -12 dB/octave @ 75 Hz, and -12 dB/octave @150 Hz settings.

414 SERIES HISTORY

The AKG 414 Series of microphones continue a long tradition of excellence that starts with the legendary C12 tube mic, with its equally legendary CK12 capsule able to produce nine polar patterns. The cylindrical C12 morphed into the smaller trapezoid shape of the C12A and C12B when the miniature Nuvistor tube was adopted. It morphed again into the C 412, the first of the FET designs, which had a choice of three polar patterns, and then into the C 414, which had four patterns.

The big change came in 1976 with the C 414 EB. The prior mics used a trapezoid-shaped adapter to provide a stand mount as well as cable output. The EB model was the first to use a built-in XLR output, thus taking on the iconic form that the 414 Series retains to this day. The other major change was the addition of switches for -20 dB pad, and bass rolloff. But the biggest change came during the middle of the production run of the EB model, when AKG discontinued making the elaborate and expensive CK12 'brass ring' style edge-terminated capsule, and replaced it with a CK12 that used a teflon ring to hold the membrane in place. With the change to the newer CK12 capsule, the modern era of the 414 Series began.

From the original brochure:

"Although based in the lineage of famous AKG large diaphragm microphones - C 12, C 12A, C 12B, C412, and C414, and also on the same one-inch gold-sputtered dual-diaphragm capsule -the CK-12- the electronics of the new C 414EB are a completely new departure, and the key to the digital level performance of the microphone. The resulting technical specifications are unique among today's microphones and will remain in the forefront of even tomorrow's microphones. The equivalent noise level of the C 414EB is at the "hushed" level of 18 dB SPL (weighted per DIN 45 405) and 15 dB SPL (A-weighted noise level per DIN 45 634, IEC 179), figures heretofore unchallenged.

"The C 414EB Microphone's maximum sound pressure capability equally outranges any other product available. For all polar patterns with zero attenuation and flat response (no rolloff, the maximum sound pressure level at 1,000 Hz for 0.5% total harmonic distortion from the electronics ... is a resounding 142 dB. With maximum attenuation selected, the figure increases to 162 dB. This results in a working dynamic range of over 124 dB, and a signal-to-noise ratio re: 94 dB SPL per DIN 45 590 of 76 dB (re: 94 dB SPL per IEC 179/A-weighted of 79 dB).

"Pre-attenuation is incorporated before the FET impedance converter stage to permit the increase of undistorted maximum sound pressure level by 10 or 20 dB for close-up recordings. This technique inhibits distortion in the transformers and circuitry used in the microphone's output and mixer inputs. A recessed switch on the front enables the user to select anyone of four different polar patterns to adjust for different recording situations.

"Four different types of microphones are thus combined in only one C 414 EB. All polar patterns are virtually frequency independent to guarantee the same sound character for all angles of incidence.

"The switchable bass-cut circuitry will reduce the risk of distortion at low frequencies. This feature is especially useful to combat wind noise and stage floor vibrations. The slope of the bass-cut filter is more than 12 dB/octave, the cut-off may be set to 75 Hz, 150 Hz, or may be bypassed (flat)."

FEATURES:

• Solid state multi-pattern condenser microphone with brass CK12 capsule
• Large, one-inch dual-diaphragm system
• Selectable cardioid, omnidirectional, figure-of-8, and hypercardioid polar patterns
• Pre-attenuation (0, -10, -20 dB) and bass attenuation selectable on the microphone (0/75 Hz/150 Hz)
• Exceptionally wide dynamic range
• Low self noise