It is replacement fuse for below products. You can buy the fuses here if they are broken, or just for spare.
2 Amp, 20mm Length, 5 mm Diameter: 12V LED Dimmer and Strobe Remote Switch
3 Amp, 30mm Length, 6 mm Diameter: Car Cigarette Lighter Plug
12V LED Dimmer and Strobe Remote Switch
Car Cigarette Lighter Plug