Feinwerkbau 7.5 Joule Spring for Feinwerkbau model Sport air from 2014-18 only #3.2.997.138

1x Genuine Feinwerkbau Main Spring that will fit mod. Sport rifle
This model was a reissue of the popular 124.
Made from 2014 and 2018
#3.2.997.138
7.5 Joules version good for +-500fps
May not fit older/prior version
 
Spring specs:
I.D 17mm
O.D 23mm
Wire - 3.0mm
Gap between coils 5.40mm
Length - 275mm
33 coils.