I will be offering this soon depending on the response. Made of silicon bronze and lengthens stock valve by 1 5/8ths, the difference in length between a 2240 and 2250 tube. 2250 tube would be optimal setup, using a 2240 endcap. The spring and co2 piercing (if you choose to use a 12 gram) are up to you. I know that there are endcaps out there that pierce the cartridge. This valve extension could definitely be used for bulk fill applications. Also let me know if you are interested in longer extensions. I can make them for you. Call me at 3609293589 or email me at sonargodz @ hotmail.com. Take the spaces out of the address.