I needed some 4 amp fuses for my '79 Twin this past week and nobody local carried them. I went everywhere from the hardware stores, home improvement centers, and even a place that restored old arcade games, but all that I could find were 1,2,3, and 5 amp slo-blo / delay fuses. I even had one shop tell me that there was no such animal as a 4 amp...clearly wrong. Anyway, so I had to go online and found several retailers offerring slo-blo fuses in all amp ratings. Ended up with a deal for a large box containing a dozen containers of 4 amp, 250v, 1-1/4, 1/4 slo-blo fuses. All seemed well and I was set for life. The problem is the fuse appears different than any delay fuses that I have used before. The end caps do say 4 amp, 250v, slo-blo, but the inner coil looks quite a bit...well, cheap and dangerous. Instead of the coiled wired all the way from cap to cap, there is a blob of solder halfway between the caps. I am no electronics guru, but that doesn't look like that would be all that accurrate nor safe to use. Would it actually fail at the right rating or not...seems like solder would be unpredictable. Are these actually some fake tubes made off-shore or are the just another design? More importantly, are they safe to use to protect my transformer?