The SDU-5/E light equips aircrew members and shipboard personnel with a high-intensity visual distress signal. The infrared filter and blue flash guard, contained in the SRU-31/P survival kit, are used in conjunction with the SDU-5/E light for signaling purposes in combat areas. The SDU-5/E is commonly called a strobe light. It emits a high-intensity flashing light. This light is visible for great distances at night. The Strobe lights were used by SOG recon teams to signal extraction aircraft.

Here you see the pouch has been attached to the Stabo Harness.