I had to scrounge some of this together from a Google search and a visit to the Wayback Machine, so here it is in one place: Take, for example, "F800mAL250V" | F | "Fast Acting" (See below) || 800mA | 800 milliamps (if you have to substitute, go lower) || 800mA | 800 milliamps (if you have to substitute, go lower amps) | | L | General Application, Normal Blow. Protection of wiring || 250V | 250 volts (if you have to substitute, I am pretty sure you want to go higher) || 250V | 250 volts (if you have to substitute, go higher volts) | ! Electronic European Fuse Markings |FF or UR | Very Fast Acting, Semiconductor Protection Fuse | |F | Fast Acting Fuse| |M |Medium Acting Fuse| |T or a Snail Shell | Slow Acting Fuse| |TT | Very Slow Acting Fuse| ! Industrial European Fuse Markings (gL, gG, gB, gTr, gR, aM, aR) !! First letter | g | Full Range | | a | Partial Range | !! 2nd Letter | M | Protection of electrical motors. Capable of withstanding motor starts. | | L | General Application, Normal Blow. Protection of wiring. | | G | General Application, Normal Blow. | | B | General Application, Normal Blow. Robust design for mining application. | | Tr | Transformer Protection. | | R | Very Fast Acting. Semiconductor Protection Fuse. [What is the difference between aR and gR?|http://web.archive.org/web/20060820075807/swecheck.com.au/frames/ar_versus_gr_index.html] |