A single Extended Magazine Spring from KWA Vector 50rd magazines, Part #357.
This is an original KWA part salvaged from new magazines.
All packages are insured! :)
"Worst Case" lead times are below, but your order may ship earlier:
1-2 Month Lead Time: WE M4 depending on resupply delays.
2-Week Lead Time: KWA Vector Adapter
2-3 Day Lead Time: Stock Adapters, Kyle/Meme Amplifiers