This is some of the specs. that I could find
I couldn't find anything on the 855...
Tony Rome


845 SENNHEISER
Frequency response (microphone) 40.....16000Hz
Sensitivity in free field, no load (1kHz) 2,0mV/Pa bei 1 kHz = -54dB (0dB = 1V/Pa) = -74dB (0dB = 1V/ubar)
Nominal impedance 350 ohms
Min. terminating impedance 1000 ohms
Dimensions 47 x 186 mm
Weight 330 g

822 SENNHEISHER
Pick-up pattern: Cardioid
Frequency response: 80 --12,000 Hz
Sensitivity (free field,no load at 1 kHz): 1.5 mV/Pa
Nominal impedance: 350 Ohms
Min.terminating impedance: 1000 Ohms
Dimensions:1-4/5" x 7-1/10"
Weight:12 oz.


E835 SENNHEISHER
Pick-up pattern cardioid
Frequency response 40–16,000 Hz
Sensitivity (free field, no load) (1 kHz) 2.7 mV/Pa at 1 kHz, nominal
Nominal impedance 350 O
Min. terminating impedance 1 k
Dimensions in inches 1.89 x 7.08
Weight 11.64 oz


815 SENNHEISHER
Dynamic mic
Precision manufactured in Germany
Cardioid pattern
Metal construction
Internal shockmounting
Hum-compensating coil
Neodymium ferrous magnet with boron
On/off switch that can be locked in on position
80Hz - 12kHz frequency response
Includes 10-year warranty

835 SENNEISHER
Pickup pattern: Cardioid
Frequency response (microphone): 40-6000Hz
Sensitivity in free field, no load: (1kHz) 2,8mV/Pa bei 1kHz = -51dB (0dB = 1V/Pa) = -71dB (0dB = 1V/ubar)
Nominal impedance: 350 ohm
Min. terminating impedance: 1000 ohm
Dimensions: 47 x 181 mm
Weight: 330 g