Orange Mod Works Retaliator, Recon MKII, Rampage, Elite Alpha Trooper, Sharpfire, Doominator, Stormtrooper Deluxe Blaster, Mega Bigshock, Grip Blaster, & Ionfire Upgrade Spring (5+ Kg) 5kg custom fitted upgrade spring. Compatible With: Retaliator, Recon MKII, Rampage, Elite Alpha Trooper, Sharpfire, Doominator, Stormtrooper Deluxe Blaster, Mega Bigshock, Grip Blaster, & Ionfire. Mod at your own risk! Increasing the spring tension can break or damage stock internal components of your blaster. Some blasters are extremely hard to reassemble, and we won't be able to troubleshoot problems due to user error. Blaster not included.