Those are fuses, what can you say? They work, the plastic case is solid and the pens are of good quality. Power rails and small basically correspond to the nominal amplifiers. With cheap ones, they may burn out too soon or not at all, blowing out the devices instead. You really want to trust expensive non-standard branded devices. Don't skimp on something that protects your belongings. You wouldn't lock your house with a luggage lock. You gotta be special or trash to get over, under, or over 3 with me.