BOW MASTER Aluminum Loading Nozzle Set for UMAREX / VFC MP5 Gen 2 GBB Airsoft - NPAS V2

At first glance it is the best possible upgrade for the mp5.

Second you install it and try it out, you will notice the adjusted npas will not stay put, but instead will reset to the highest power output (3.5J 0.32g bb).

Disassembling it the first time you will notice the go through pin that has threads will round the flathead meaning you might have to punch it out.

A saving grace is that it takes the plastic nozzles rear end, meaning you can use aluminium and plastic rocket valves.
You can also add different glues to the npas to make it stay adjusted (I used loctite 542).

I would still recommend the part, since the original plastic ones feeding peak tends to break.