The Schneider Electric DF3FN25 is a cylindrical NFC cartridge fuse from the TeSys GS range, sized 22 x 58 mm and rated 25 A at 690 V AC. It follows a gG (general-purpose) fuse curve, meaning it provides full-range overcurrent protection for cable and equipment — not just short-circuit, but also overloads down to the fuse's minimum operating current. The striker (local signalling) pops out when the fuse blows, which can trip a microswitch or simply give a visual indication on the panel door.
The 25 A rating at 690 V AC is the continuous current the fuse can carry without nuisance opening, at the maximum system voltage. The 22 x 58 mm body is a standard European fuse-link size (often called "NH00" in some contexts, though this is the cylindrical cartridge variant). The gG curve means it coordinates with typical motor-starting inrush — it will hold a brief surge but clear a sustained overload. The striker is a mechanical flag; if your fuse holder expects a striker to trigger an auxiliary contact, this part provides that. Supplied as a set of 10, which is the standard packaging quantity for this line.