ines ▁as ▁a ▁means ▁of ▁en han cing ▁reli ability . ▁The ▁magnetic ▁coupling ▁has ▁several ▁advantages ▁over ▁a ▁traditional ▁stuff ing ▁box . ▁ ▁Some ▁aqu arium ▁p umps ▁are ▁ ▁magnetic ▁drive ▁p umps ▁-- ▁they ▁use ▁magnetic ▁coupling ▁between ▁the ▁motor ▁on ▁the ▁dry ▁side ▁of ▁an ▁aqu arium ▁wall ▁and ▁the ▁prop eller / imp eller ▁in ▁the ▁water ▁on ▁the ▁other ▁side ▁of ▁that ▁aqu arium ▁wall . ▁With ▁two ▁face - to - face ▁magnet ized ▁dis ks ▁-- ▁one ▁driving ▁magnet ▁on ▁the ▁dry ▁side , ▁and ▁another ▁driven ▁magnet ▁on ▁the ▁wet ▁side ▁of ▁the ▁glass ▁-- ▁there ▁are ▁two ▁options ▁for ▁design ing ▁the ▁magnetic ▁pattern ▁on ▁each ▁disk . ▁One ▁option ▁bal ances ▁the ▁( att ract ive ) ▁section ▁that ▁trans fers ▁tor que , ▁with ▁magnetic ▁rep ulsion ▁near ▁the ▁axis , ▁to ▁nearly ▁cancel ▁out ▁ax ial ▁load . ▁The ▁other ▁option ▁designs ▁the ▁magnetic ▁pattern ▁to ▁maxim ize ▁the ▁tor que , ▁and ▁uses ▁a ▁mechanical ▁thrust ▁bearing ▁to ▁resist ▁the ▁att raction ▁between ▁the ▁magnet ized ▁dis ks . ▁ ▁A ▁magnetic ▁stir rer ▁is ▁another ▁example ▁of ▁magnetic ▁coupling . ▁ ▁Mag net ic ▁cou pl ings ▁are ▁often ▁synchron ous ▁( output ▁sh aft ▁speed ▁equals ▁input ▁sh aft ▁speed , ▁or ▁ 1 : 1 ). ▁ ▁The ▁first ▁few ▁g ears ▁in ▁the ▁ge art rain ▁of ▁an ▁Om ega ▁Meg ason ic ▁w rist watch ▁have ▁no ▁teeth ; ▁instead ▁magnetic ▁north ▁and