United States Navy E-4/5/6 Machinist's Mate Rating Badge
Criteria: Worn by Machinist's Mates (MM) with ranks from Petty Officer 3rd Class (E-4) to Petty Officer 1st Class (E-6). Machinist's Mates are typically responsible for the continuous operation of the engines, compressors, refrigeration and air conditioning equipment aboard the USN's vessels and at their land based installations. Some Machinist's Mates are also trained in Health Physics and maintaining of reactor chemistry for their work required for the maintenance of the machinery involved with nuclear reactors.
The badge is sold with all 3 chevrons below the rating for E-6, and can be tailored down to the other two chevrons.