This is a set of five Atomos Master Caddy II units compatible with the Shogun and backwards-compatible with all previous Atomos monitor/recorder models. The Master Caddy II supports standard 2.5" SSDs and HDDs and features dual key insertion (groove/slit on both sides) in contrast to the original Master Caddy's single key insertion. The Master Caddy II is replacing the original Master Caddy as the standard caddy for all Atomos monitors/recorders. (The original Master Caddy is not compatible with the Shogun.)