AR-15 Hera Arms Multi Purpose Safety Selector (MPSS) A new innovation to the AR15 world is here. The MPSS, Multi Purpose Safety Selector, is introducing a dual purpose safety bolt as well as 5 interchangeable polymer switches in 3 colors; for a total of 15 switches, giving almost endless configuration. The dual purpose safety bolt may be used in a 45° or 90° fire mode. By easily rotating the bolt 180° you can choose between standard or short fire selections. Each Polymer switch comes in 5 various lengths and sizes as well as in Black, Flat Dark Earth and Foliage to assist the shooter in finding the perfect combination.