Matrix Ressort de mise à niveau Airsoft AEG à pas irrégulier (puissance: M115 350 ~ 420 FPS)/Matrix Irregular Pitch Airsoft AEG Upgrade Spring (Power: M115 350~420 FPS)   Matrix 170% / M115 Irregular Pitch Airsoft AEG Upgrade Spring (350~420 FPS) These Matrix springs are build after careful study of major...

Angel Custom PSS2 Mega-Up APS / Type96 Power Up Spring - SP150 (420~520 FPS) Features: Oil Tempered with high pressure treatment Progressive design, or "Irregular pitch", minimizes spring resistance making it easier to pull the bolt back Constructed out of 1st class carbon steel piano wire Long lasting durability and...