Bought a mixed box of mini blade fuses today from Halfrauds as I knew a few of the things in my car that weren't working (cigar lighters etc) were most likely to be fuse related.

Turns out they were - I love a simple fix!

Anyway - these fuses are awesome (and yes, that's possibly the saddest thing I've ever written). When they blow (I blew a couple sorting out a rear lamp issue) - they have a red LED in them that lights up!

It's a game changer! Have these been around for a while and I'm just late to the party?

Almost tempted to change ALL the fuses for these LED types, given the less than stellar electrical reputation of the L322. Just means that if a fuse goes pop it's immediately obvious. Could save a lot of faffing.

Anyone else seen these little bad boys before? I hadn't. Past (too many to list, but a few favs)...
2007 Porsche 997 C2S Coupe
2007 FFRR 4.2 S/C
2012 Jag XKR 5.0 S/C
2014 Merc SL500 AMG 4.7 V8 BiTurbo (remapped to 560BHP)
2011 FFRR 4.4 TDV8 Vogue SE - Overfinch Conversion
2012 Porsche Cayenne Turbo
2018 AMG C63S Estate
2015 Mercedes GLE63S
2017 Maserati Levante Diesel
2017 Audi A6 Avant 3.0 Black Edition

Never heard of these, looking on the Bay now  MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

but who doesn't love faffing? Dan

2002 Zambezi Silver

Men And Motors RR Quote - It's like having wheels fitted to your living room!

You're slightly late to the party, buffet hasn't been served yet though

Seen them in Halfords a few times before, I was baffled to how they actually work! 

I would assume that the LED (with its voltage reducing resistor is wired across the 2 blades. When the fuse is good, then both sides will be either 12v (nominal) or 0v. If the fuse blows, then the ends of the fuse are different voltages and the LED light. The dropping resistor will also act as a current limiter

No idea how they work. I was going to say automagic - but Berkshirelad's answer is probably slightly more accurate.

All I know is it's bloody handy having a little red glow showing you the culprits in the fuse box. Past (too many to list, but a few favs)...
2007 Porsche 997 C2S Coupe
2007 FFRR 4.2 S/C
2012 Jag XKR 5.0 S/C
2014 Merc SL500 AMG 4.7 V8 BiTurbo (remapped to 560BHP)
2011 FFRR 4.4 TDV8 Vogue SE - Overfinch Conversion
2012 Porsche Cayenne Turbo
2018 AMG C63S Estate
2015 Mercedes GLE63S
2017 Maserati Levante Diesel
2017 Audi A6 Avant 3.0 Black Edition

Just as an FYI there seem to be two types. Cheaper ones have the LED protruding out of the top of the fuse, the ones I have look exactly like standard fuses with the LED built in. Past (too many to list, but a few favs)...
2007 Porsche 997 C2S Coupe
2007 FFRR 4.2 S/C
2012 Jag XKR 5.0 S/C
2014 Merc SL500 AMG 4.7 V8 BiTurbo (remapped to 560BHP)
2011 FFRR 4.4 TDV8 Vogue SE - Overfinch Conversion
2012 Porsche Cayenne Turbo
2018 AMG C63S Estate
2015 Mercedes GLE63S
2017 Maserati Levante Diesel
2017 Audi A6 Avant 3.0 Black Edition

Surprised halfords sell um. Bet they are expensive.

No don't change them all !