Click to expand Tap to zoom KWA RM4 ERG CQB Low Power Main Spring by KWA Out of Stock $29.99 SKU 199-1601-0388 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Out of Stock This replacement part is displayed as part number 388 on RM4 CQB diagram. Part 199-1601-0388