The Siemens SENTRON 5SL6301-7RC is a 3-pole miniature circuit breaker rated 1 A with a C tripping characteristic and a 7.5 kA breaking capacity per EN 60898.
Rated 440 V max in multi-phase operation, so it handles 400 V three-phase supplies with headroom.
Depth is 76 mm, installation depth 70 mm; the 90 mm height and 54 mm width (3 modular units) fit standard enclosure cutouts. Sealable — you can lock the toggle position with a padlock for lockout/tagout. Rated for 10 000 mechanical switching cycles — typical for an MCB in a panel that sees occasional manual operation plus automatic fault clearing.