MechLabs XX-Mod Fully Mechanical HPA Engine - BlueMechLabs XX Mod Fully Mechanical HPA Engine Blue Upgrade your airsoft game with the MechLabs XX Mod Fully Mechanical HPA Engine in striking Blue. This high performance HPA engine is engineered for serious players seeking unmatched reliability, consistency, and power on the field. The XX Mod features a fully mechanical designno batteries or electronics requiredensuring flawless operation in any condition. Compatible with most popular airsoft AEG