The Musiclily Pro Hardened Steel 5/32 inch (or Metric 4mm) Allen Key Hex Wrench is a great tool for truss rod adjustments. I got the 4mm size, and as you can see in the photo, it fits perfectly on my Ibanez AZ. This size is pretty standard for most guitars, but I’d recommend checking your guitar’s specs beforehand to be sure—it’s frustrating to get the wrong tool and realize it doesn’t fit.The design is simple but well thought out. It’s essentially a wrench with a handle, but the blue, spotted grip gives it a polished, professional look. It feels sturdy in the hand and doesn’t come across as cheap. At around $9, the price is reasonable, especially when you consider how much it can save you compared to a trip to the repair shop.For people like myself who aren’t luthiers or skilled guitar technicians, I’d recommend starting out with a cheaper guitar so you don’t risk damaging your expensive one. The packaging even includes a disclaimer that they’re not responsible for any damage caused by misuse, which is a fair warning. Always make small, deliberate adjustments to avoid causing any issues.Overall, this is a reliable and handy tool for basic guitar maintenance. It’s affordable, well-designed, and does exactly what it’s supposed to do. For someone like me, who’s primarily a player rather than a technician, this tool makes it easy to tackle small adjustments at home. If you’re careful and double-check your specs, this is a great addition to your toolkit and well worth the price!