They appear to be the exact same as the Neiko wire strippers. They are only $11.04.
I can't post a link because I don't have enough posts, but they are Neiko 01924A on Amazon.
I own both the irwin and neiko pairs. For my needs they function the same and may very well be from the same manufacturer as you suggest. I'm very happy with both pairs, though I don't use them every day like an electrician might.
I do notice the insulation doesn't fall out sometimes, but it doesn't bother me. Some types of wires react differently, but once you get a feel for how to treat each one, they will usually perform just fine. I like being able to strip an outer jacket, and I love being able to strip multiple wires at once.
At the time I paid 13.99 for the neiko in august of 2017, and 12.08 for the irwins in february of 2018.