There are many fake Bussmann fuses in fuse market, to make sure the fuse you buy is the true one， Here are some tips for reference:

1, From the country of Origin

Each Bussmann fuse with unique manufacture location.

E.g: 

1), Bussmann FWJ series fuse manufacture location: Hungary

2), Bussmann NH fuse, PV fuse  is made in India;

3), Bussmann  170M series fuse, most EV fuse is made in China;

Sometimes you will find there are some similar PN's: Such as 170M6812D, and 170M6812;

Are they the same product? How to tell which one is fake, which one is genuine?

170MxxxxD series  high speed fuse manufacture location: Hungary 

170MxxxxD is the original Part Number, when production line transferred to China on Year 2008, The "D" is removed;

170Mxxxx is made in China.

So when we see: 170Mxxxx,  the fuse is marked:" Made in Hungary" It's fake. Also, when 170MxxxxD, when the fuse is marked:" Made in China" it's probably the fake fuse.

Similar with the 12TDLEJ63 and 12TDLEJ63-XA, The PN difference only with or whinout "-XA".

12TDLEJ63  is made in India:

12TDLEJ63-XA is made in China.

Bussmann with 2 locations, it's because these PN's are popular in China and globally.

Also FWH series,  FWP series,

FWH-150B, FWP-150A is made in Mexico;

FWH-150C, FWP-150C is made in China.

The FWH-150B production line will tranferred from Mexico to China continuously. So in the market, there should be less and less FWH-B fuse.

2, NH fuse

This is a picture genuine vs fake NH fuse. From the picture we can see:

1) , The fake NH fuse, surface is very smooth and beautiful, The genuine Nh fuse, there are many grid lines on the surface.

2),  On the fuse blades, the fake fuse surface is tin plated; True Nh fuse is silver-plating, so it will looks dark, this is the characteristics of silver, It's easily to be oxidized in air.

But for electrical connection performance, Silver is perfect,  which the cost is also much higher then tin or other plating.

3), The fake fuse this whole is no function, it will looks very beautifil;

Genuine Bussmann fuse use this hole to fill sand, after the process, the whole will be sealed with soldering and a red cover.

3, Bussmann 170M series 

This is Bussmann popular fuse, so, with a lot of fake fuse.

There are some key points to check and pick out.

Pls review the article: How to tell if a 170M Fuse is genuine or fake?

4, Continuous adding content......