R4

R4 is a designation used for several unrelated items across technology, military equipment, and infrastructure. The meaning of R4 depends on context, and the term appears in multiple countries for different products, so it does not refer to a single item.

R4 (Nintendo DS) refers to a line of flash cartridges for the Nintendo DS family. First released in the late 2000s by the R4 DS Team, these devices use a microSD card to store software and games and run firmware such as TTMenu or similar loaders. They enable loading homebrew applications, emulators, and backups of DS games on original DS and DS Lite hardware. Later variants added support for microSDHC cards. The use of R4 cartridges to play pirated content has raised legal questions and varies by jurisdiction.

R4 in firearms denotes a 5.56x45mm NATO assault rifle used by the South African National Defence Force. It is considered a derivative of the AR-15/M16 family and is known for modularity and adaptability across various configurations, including carbine forms. The R4 has played a significant role in South Africa’s military equipment inventory, with revisions and related models evolving over time.

Other uses of the designation exist as well. The R4 label appears on various regional highways and routes in different countries and serves as a model or product code in electronics and other industries. Because R4 spans multiple domains, clarity depends on the specific context in which it is used.