ZCI M90 Spring

These ZCI springs come in stiffnesses from M80 up to M150. Maintaining ZCI's trend of maximizing performance per cost these are just bare springs, removing the cost of packaging and adding shipped expense. No FPS estimate is given because as with all spring ratings there are so many other factors that effect FPS the given value would be almost arbitrary.

These springs have a VERY low spring constant so are ideal for super low FPS CQB setups. These are so weak that they should be used carefully to avoid pre-engagment.

Specifications:
Wire gauge: ~1.19mm (.047in)
Type: M90

UASR rating: 2.54L
Spring rate (6kg test): 454N/m
Spring length: 183mm
More information on UASR ratings here and here.