You can get these now for pretty cheap on Amazon, not sure if the quality is as good, but it's just a hook that slips into your rack, so can't be all that difficult to match this. I think this was the only option around for 5/8" racks when I went looking for them. They are similar in experience to a Wall Control attachment - they fit fine but will come out of the hole when you take off the thing it's holding. So, for instance, my kid likes to put a bar up on these when he's using the lat pulldown (so the bar is on the inside of the front uprights of the rack, if that makes sense, so he has room in front of him to access the lat pulldown without the barbell interfering, and without having to take the bar fully out of the rack. So when I put the bar back on the jcups or monos, this wants to come up out of the hole with the barbell.
Besides that, works fine, easily can store whatever needs storing close by for today's session. I'd recommend, but honestly, would have probably gone with the cheapos on Amazon if they had them at the time.
Performance
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Build Quality