Like the Elenco ST74 ST74 AC Line Splitter, this product has a X1 and X10 current loop transformer and a line / neutral banana jack for measuring voltage.
You can read my review on the ST74 for the advantage of having a X10 loop to use with your meter, but this design lacks some desirable features found on the ST74.
I should point out that both products insist on hanging from the outlet supplying power. This is fine for a new, high quality outlet, but often problems happen with old, worn out jacks that barely grip a heavy cord. Remember that the outlet must support both these devices and the weight of your amp clamp.
The missing features here are:
1 - there is no banana jack for "EARTH/GROUND". Since outlets can be miswired, or have an open earth connection, this is an important line to be able to probe safely. The ST74 has this jack
2 - the output jack to your appliance is ONLY for the US standard. This is fine most of the time, but on the rare chance you need to test a foreign plug, the "UNIVERSAL" jack on the ST74 will let you plug almost any power cord into it.
3 - Finally the ST-74 costs a little less. I do think this is better built than the ST-74, but that's just from "feel" of the product. Both products "hang" off the power outlet you put them into and lack a 6" or 12" power cord, which would be nice to accommodate inconveniently located outlets or outlets that won't support the extra weight of a current transformer + amp clamp. I would give this 4 stars if it had a power cord and 5 stars if it had a ground jack as well as the line and neutral. I've seen too many worn out power outlets that won't hold onto an adapter plus an amp clamp.
If you don't care to measure ground impedance, don't think you'll ever work on foreign power cord devices, and have some more money, then its fine for you. But the ST-74 still does more for less and is a better value.