Precision would allow better working machinery, interchangeability of parts and standardization of threaded fasteners. There are at least four levels of standardization&colon; compatibility, interchangeability, commonality and reference. These engines are known for their extreme reliability, durability, and parts interchangeability. A classification system exists for ease of manufacture and interchangeability of fabricated threaded items. To allow easy functionality and interchangeability, these are designed to have standardised dimensions. A second suggestion Quine considers is an explanation of synonymy in terms of interchangeability. Furthermore, there are a number of variations with NMTB tooling that make interchangeability troublesome. Defining and achieving classes of fit are important for interchangeability. However, each factory produced slightly differing parts, leading to interchangeability issues. This allows for a much wider range of cartridge interchangeability at less expense. Model L rifles extend to the interchangeability of certain parts. This modular interchangeability became a staple of Lego Space until 1995. Maintaining 80% service parts interchangeability with the -ton models was of great value. The two vehicle types share a 95% interchangeability of automotive parts. Behind-the-lens shutters were used in some cameras with limited lens interchangeability.