AXIAL FERRITE BEAD ON LEAD
These are a small ferrite bead on a tinned wire, manufactured by Philips.
They come preformed with a 5mm pitch, length when wire is straightened out is about 60mm.
Apparently 2 of these with a ceramic capacitor to ground in the centre make a good RF blocking 'T' filter.
Dimensions of the ferrite are roughly 3.5mm outer diameter and 4mm length.
Priced and supplied in packs of 5pcs