There are two types of kits
The AB3 kit
Includes a 9.5 cm 31.5 coil spring spaceing and wieghting , dramaticaly increases power while maintaining a smooth shooting cycle and easy cocking ..the fast lock time helps the rifles accuracy too .
The AB3 XL kit
Includes a 10cm 35 coil spring , spaceing and wieghting ,
This kit makes maximum power , while avoiding a harsh cycle .
these are high quality kits , once you try them your CZ 630 /631 will be a whole different airgun !
Link ....
www.airgunforum.ca/forum/...9505#39505 Regards,
Frank
