A weird little magnet - made from C1/Y10T grade ceramic ferrite - and, honestly, not used for a whole lot nowadays - BUT - the have one historic point of note in history - this is the same spec of magnet used in the original Burns® Trisonics.

Specifically, 2 bar magnets are inserted into the space in the "air coil", adding "the charge" and making the whole pickup work.

These are the bar magnets commonly found in Gibson® firebird mini humbuckers - used as a magnetic pole within the bobbin, resulting in a very different tone.

One of the "oddity" sizes of bar magnet - sometimes turn up in P90s, sometimes turn up in Mini-buckers, very rarely, even in full sized humbuckers. As always, worth checking the sizes to make sure this is the one you need.

Humbucker and P90 sized Bar magnets, available in Alnico 2, 3, 4 and 5

58mm x 12.5mm x 3.2mm

Oversized bar magnets usually turn up in higher output pickups, and are a fantastic way to get a really unique tone.

Humbucker and P90 sized Bar magnets, available in Alnico 2, 3, 4, 5, 6, 8 and ceramic

62mm x 12.5mm x 3.2mm

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Oversized bar magnets usually turn up in 7 String humbucker, and are a fantastic way to get a really unique tone.

Oversized bar magnets usually turn up in higher output 7 string pickups, and are a fantastic way to get a really unique tone.

8 String Humbucker bar magnets, much longer then a standard magnet to cover the wider pole spacing.

Oversized bar magnets usually turn up in higher output pickups, and are a fantastic way to get a really unique tone.

Humbucker and P90 sized Bar magnets, available in Alnico 2 and Alnico 5

62mm or 58mm x 12.5mm x 3.2mm

Steel bar for mounting humbucker pole screws efficiently against the magnet.
Available in 49.2mm, 50mm and 52mm.

Steel bar for mounting humbucker pole screws efficiently against the magnet.
Available in 57.6mm and 61.2mm

Steel bar for mounting humbucker pole screws efficiently against the magnet.
Available in 71.6mm

Replacement bar magnets for single coil sized/Hot Rail pickups such as the Axesrus® TT series, DiMarzio® Fastrack line and similar pickups.

Magnetic spacers are a novel little idea, and turn up sporadically on production pickups every so often. Essentially, they replace the inert maple or plastic spacers either side of a Humbuckers poles to alter the tone, usually by making a pickup more aggressive.

Maple Humbucker Spacers

Plastic Spacers for Humbuckers

Plastic Spacers for Humbuckers