I have a brand new Harlan Engineering programmable window switch for sale.

Here are the specs off Harlan's website:
Dimensions: 1" diameter by 3" long
Housing: Flat black Polycarbonate
Usable on all ignition systems (distributor, distibutor-less, 2/4/6/8 cylinders)
Adjustable in 100 RPM steps from 500 RPM to 12000 RPM without additional pills or modules
Operation and Installation instructions included.
Grounding output capable of sinking 0.5A of current

I was going to use it to control the activation of my nitrous, but my friend who did the nitrous install was more familiar with the MSD window switch and I ended up using one of those.

By brand new, I don't mean that I hooked it up and took it back off before using it. It's never been hooked up-- the wires are as they were when they left the factory.

Looking for $40 shipped in the Continental 48 US states. I do take PayPal or USPS money orders.

 

is 0.5A good enough to ground a nitrous setup? All the others seem to be capable of 1.5A...

 

I'm not the engineer who designed it, just a guy who bought it. I would assume since Harlan has sold these for years, and hundreds of people are controlling their nitrous setups with them, that they are appropriate for the purpose intended.

Again, I'm not an engineer. You may want to contact Harlan directly.