The DF2LA1251 is a DIN NH4 blade fuse from the Schneider Electric TeSys range, rated 1250 A at 500 V AC with an aM (motor-protection) time-current curve. It is a single-piece fuse without striker, intended for motor branch-circuit protection in industrial distribution panels.
The 1250 A rated current at 500 V AC means this fuse is sized for large motor loads or feeder circuits where the full-load current approaches that level. The aM curve is designed to withstand motor inrush without nuisance opening, while still clearing short-circuit faults. The NH4 blade size is a standard DIN form factor — verify your fuse holder or disconnect switch accepts NH4 dimensions before specifying.