This is sold on eBay as 2.4 GHz counter (manual, translated manual). But the one that I bought it has MB501L which is 1.1 GHz !!!
The good news is that it has VC-TCXO and it is stable. You can adjust the frequency if you have a frequency standard. You adjust the trimmer next to TCXO. The dynamic range in the 500 MHz range is very small. If the signal is less than needed it shows a frequency that it is near the real one.The RF input connector is improper for this frequency. I extract it and solder a BNC one with small leads. It has one input and you can choose to display with or without the prescaler. It has also a auto future which works fine. It has IF shift option setup but I did not test it. Generally it is a good choice compared with the low price which is near the cost of the components.
Here you can find manuals from similar products from the same designer. Note the PLJ_5110C !!!