They are extremely high interrupting rating fuses: 440VDC, with large band of ratings (current rating 2 to 50A).
High-Speed Cylindrical Fuse Protistor® Size 14x51 gLB 440VDC IEC 2A With Striker
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 25A
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 25A With Striker
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 32A
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 32A With Striker
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 40A
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 40A With Striker
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 50A
High-Speed Cylindrical Fuse Protistor® Size 14x51 gR 690VAC IEC 10A With Striker