WEM Mk4 Copicat - low volume output

[Bushbaby]

Good Evening all
Please see the pics of the replacement refurbished heads that I have purchased for my copicat unit. These are indeed brass and surprisingly heavy for their size. I have shown them in order from erase to playback 3. i have no idea what the values should be so I do welcome your thoughts and comments. 
They were good value assuming that I can use them in the unit??

Best Regards