Strong ring countersunk magnet for speaker magnet

Tip:
1. Strong magnets should keep away from Ironware and some  easily magnetized iron products, such
as monitors, bank cards, computers, televisions, mobile phones and other.
2. Strong magnets should be stored in a dry, heated environment, and need to use of plastic, wood,
cardboard, foam to separated and wrapped.
3. Magnets might be interested in water meter ,electric meter, gas meter and some metering equipment
exist some inaccurate affect (such as: if magnets placed near  the meter, the meter will slow down).