At just under 38 Dollar this looks like a great upgrade. Unfortunately I don’t own an MP5, but if I did…

It works with HK firearms like the G3, HK91, HK33, 53, 93 and the MP5 and MP5Ks (full list below).

It works with all semi & full auto trigger packs, but not with the burst trigger packs.

Below: Detailed picture of the flat trigger.

Enhanced HK Machined All Steel Flat Trigger – USA

Made in the USA from solid billet machined ordnance grade steel, heat treated, finished in a QPQ Nitride finish. With the utmost attention to detail in the design and manufacture of the HK Parts flat 90 series trigger. Each enhanced flat trigger will fit all 0,1 & SEF & Navy style trigger packs. Each trigger counts as one US made compliant part needed for builds & conversions for US compliance of 922R. Fits all 90 series styles of firearms. Compared to a factory HK trigger this trigger will make the pull and feel much better than a stock factory trigger. A huge improvement over a stock HK trigger.

Qualities & features of each enhanced trigger:

• Works for both semi & full auto trigger packs (not burst packs)
• Ordnance grade steel billet fully machined
• Full heat treated & QPQ finished in nitride
• Enhanced dimensions for the very best pull possible
• Provides unparalleled ergonomics
• Adds 1 X 922R USA made compliant part

A drop in replacement of all SEF, 0,1 & Navy Triggers

• HK91, G3, PTR
• HK93, 33, 53
• HK MP5, MP5K
• Zenith, Omega, POF, etc
• Clones or other custom builds

Here you can see the serrated positioning grooves with comfort induced tapered edges.

You can find the link to the new flat trigger here.