A guy I've known since '89 has made a lot of $$$ with his line of automotive tools.
A couple are copies of someone else's, most are improved versions, and a couple are his own ideas.
Most of it he has made in India, and some gauges he sources from China.
He quality-checks all of it, and there's a % of send-back - more on the Chinese stuff than the Indian.
Been that way since before I met him. He says having the stuff made in the US would render him un-competitive.
His market is at the lower-price end, as that's the volume needed.
Near as I can tell, his profit margin runs 50-100% depending on the item, and a number of places retail his stuff, including Summit & Jeg's.
He's an adept & clever businessman, and has also made a ton of money in commercial property.
He registers original things as opposed to patenting them, because he says patent attys are too expensive, the process takes too long, and if someone changes one thing they can knock his stuff off.
Registering things is more protective, he says.

I'm not endorsing or slamming, just providing info as told to me.