Amazon.com: CynKen 10pcs 8mm*50mm Ferrite Rod Bar Loopstick For Radio Antenna Aerial Crystal About 0.32"x2" : Electronics
Polymet - Reine Metalle. Ferrite rod 8 x 100 mm, round rod, ferrite core, round rod 10 cm antenna ferrite DCF77, soft magnetic manganese-zinc-ferrite : Amazon.nl: Business, Industry & Science