Hi guys, I would like to purchase Roko homing switches for my new build. This is the same switch Peter from CNC nutz shows in his "homing" videos #15 is a SN04-N at the 1:31 second mark. Is this a "Normally Open" type switch. Are we best off to use the "Normally Closed" type as they are safer with regard to wires breaking or coming off. I tracked down a supplier of this brand of switch, he offers them in a 'NO' or 'NC', but also the option of NPN or PNP, can u please tel me which is the correct type to purchase. Thanks in advance.