Naval Service Training Command requires 2,500 12-inch Brushed Aluminum Arms Parallel Rules to support more than 600 Naval Junior Reserve Officers Training Corps and Navy National Defense Cadet Corps units. It also requests 3,500 copies of the ASVAB Study Guide Premium (ISBN 9781506283647) and 1,200 copies of the Digital SAT Study Guide Premium (ISBN 9781506297637). The parallel rule, manufactured by Weems and Plath and sold to third-party vendors for resale, is used in NJROTC/NNDCC Naval Science navigation courses and was adopted by the NSTC Citizen Development Curriculum Manager and Curriculum Advisory Board. No substitute instrument can be used, and the Navy considers continued use of this instrument to be best value because only one responsible manufacturer exists and other instruments will not satisfy agency requirements.