Lot of request we have got from our European customer that we should start manufacturing Hatsan seal. So we did finally.
We wanted to give a little details about the product so interested people can have more insight about it.
If you see the above picture where arrow is pointing, you will see the seal is made to match the chamfering of the piston in order to BLOCK the air leakage.
In the above picture it is much evident now.
The seal is available here http://target-tune.in/international/products/SEAL-for-HATSAN-27mm-Receiver.html