TM 10-8415-206-12&P
SECTION X. INSTALLATION INSTRUCTIONS FOR OXYGEN MASK
4-33. SPH-4 HELMET ALTERATIONS.
Use the following procedures to accomplish the alterations:
SPH-4 helmets require two alterations.
The first alteration requires installation of two receiver mechanisms (Figure 3-1). The second alteration
requires installation of the boom microphone attachment (7).
Figure 3-1. SPH-4 Flight Helmet
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