I had the same experience as J. Wallis.
I bought this to replace the damaged wiring in my m16. I had to melt down some of the base so it would even fit in my gearbox, and I filed and sanded the plastic rails on the switch, because they were rough. The connectors also pull out of the housing easily, and the extension does not reach the rear of the stock, and is mini tamiya.
it's a cheap-ish replacement if you can't solder, crimp, etc. yourself
18 gauge wiring, very, very small, not much current can get through
mini tamiya (rear wiring is usually large)
low quality plastic
quality, the price reflects it.
you would be better off buying some 14-16 gauge wiring, (depends on what fits without being pinched) spade connectors, and wiring it yourself, which is what I am doing