the left hand one is the button type. pressing the button in the middle of the brass ring will close the contacts in the solenoid to turn the starter. i would suggest the one on the right becsuse there is lesss chance of anyone starting it without the key.
I second that about the right one, but the left one is useful when the starter button has broken Still, the left one is "wide open" for humidity, which usually has bad influence on electrics...
Essex Lily - Super Major -62 (No. 1618924)
Mr Fordson - Super Dexta -64(dad's)
"Si is est non infractus , effrego is quod animadverto si vos can redintegro is!"
<Ut simplex, validus quod constanter ut ferrum talea campester = Super Major>