one for each engine with twins

Install separate ignition "kill" switches for each engine. There are instances when you need to only kill one engine at a time. If you have just one kill switch wired to shut-off both engines at the same time, you can't do this. Be aware of the knock-off copies of the Mercury style cap pull-off kill switches. Use only Genuine Mercury kill switch/harness, Mercury part # 87-856654A4. Current retail is $74.60 each. This particular units use applies to both I/O's & O/B's. I cannot stress enough, how important an ignition kill switch can be. So many people have them already on their boats(Offshore, fishing, etc...) and don't use them. Ed

Here's what I have on my Formula.

Those are the ones Cuda...probably the best out there. I have some new ones available(Mercury...of course) if anyones interested. Will sell for $45.00 each shipped. Ed

I can't believe how many high end performance boats that I have seen that have NO kill switches. It makes no sense at all as to why those owners haven't spend a small amount of money for such a large safety item. My .02

While we are on the subject.

Where do you guys wear your tether? I have tried my right wrist, but killed the motor reaching for the radio Been wearing it on my right ankle lately

I clip mine on my belt loop when wearing regular pants or shorts. Most my swim trunks have a loop somewhere that I attach too. If there is not a place to attach, I use a LARGE safety pin.

watching dlaw getting tossed into the drink sold me on a set... i dont wanna go there, but if i do i dont want a 30 mile swim!

Exactly.....I believe these operators have never been hurt or thrown before. If they have, they would understand how important they are. It can't/won't happen to me attitude. Yet, in the back of their mind, they know better. The ignition "dead-man" or "kill switch" not only protects the operator, it protects everyone else in the boat AND everyone else outside the boat that could get run over. Just good common safety sense. Ed

I have a small but strong caribiner attached to mine. I usually hook it to the bottom of my swim trunks leg. Anywhere else is in the way.