2-4. Operation of Standard Components.
a. Fastening/Adjusting Chinstrap.
(1) Fasten the chinstrap by inserting the strap through the D-rings, splitting the rings, and inserting the strap back
through the inner D-ring.
(2) To tighten the chinstrap, pull it through the inner D-ring to attain the desired fit (Figure 2-8).
(3) To loosen the chinstrap, rotate the outer D-ring up and to the left by pulling on the two tabs of the outer D-ring.
Pull the strap through the inner D-ring toward the left as needed to loosen or disengage the strap. If loosening, take up
slack through D-rings by pulling the section of the strap under the chin to the right.
For most people, the chinstrap is long enough to allow for donning and doffing
without repeated lacing through D-rings.
Figure 2-8. Fastening Chinstrap