Klein Tools 50611 Magnetic Wire Puller

The magnet on this is great. It will scuff up your drywall so use a cloth under the wheels to keep your surfaces clean. Try to use a nice fishing line or something on the weight. I sometimes just fish fish sticks and the wheeler end vs the weight it comes with. Ran plenty of speaker, ether and electric with this.

I kinda always find myself using the fish sticks tho.

How long is it going to take you to design, print, and assemble your DIY version? That might make sense for a homeowner who likes (and has the time) to tinker, but if someone doesn't have that kind of time or is getting paid to do electrical work, buying the proven and trusted Klein tool is the way to go.

I'd recommend clicking the llink to review the product page, photos, and other products. There you'll see this is the low end of this type of product. It's not great and likely isn't for every need. It will do the basic job.

It probably costs more than necessary, but so do a lot of things. It does carry the Klein name, so it's likely a bit more costly than a no-name version; just checked and there's a knockoff (same color and features) that's a dollar cheaper. Again, it's basic and does the job so there's likely not a bit of room left for making something new, or yourself, and making a profit or saving money.

I do wood working and can make most furniture featured on SD, but I don't comment on the post saying, "I could do it better for cheaper and people who spend their money on it are rich fools." You kind of crashed the post with your comment that said you could do it better, cheaper, and thought that anyone who spent money on it was throwing money away.