I start with a brand new original Crosman valve stem part number 2250-016 and do all the work myself to the highest standard. I also offer a valve pinning service in another ebay listing. A perfect complimentary modification to a standard or upgraded valve.
This valve stem has a modified gas flowed stem that allows an increased volume of CO2 to pass into the transfer port. This is done by removing material from the valve stem in line with the transfer port. I also gas flow the edge of the valve seat and the area just behind the piercing pin. The third image shows a standard valve stem (on the top) vs the high flow valve stem (bottom and centre). I can also remove the piercing pin (see 2nd and 6th image) at no extra cost if you have, or are about to convert away from 12g CO2 powerlets. You will need to let me know this after purchasing otherwise I will leave the pin intact.
Any questions just ask.