|Serial number||NMI-21"NMI" can not be assigned to a declared number type with value -21.|
- 21. Solid brass case has two insulated solder contacts protruding through top plate. Unit rests on tripod like base machined as part of case. Around case, at bottom, is stamped TYPE S-35 SEISMOMETER, the TEXAS INSTRUMENTS logo, MADE IN USA SERIAL NUMBER and stamped in separately are the numbers 2392. Printed on the bottom is TI 23 within a circle.