This is a Rapax Modular 2+ joule spring which includes fps adjuster rings as well! This fits most bolt action platforms as it is a 13mm spring.
Compatibility
Can be used in Tokyo Marui VSR-10, Silverback SRS/TAC41, Well L96, Novritsch SSG10, SSG96, etc. The 13mm outer diameter will fit all above mentioned sniper replicas with a spring guide compatible with 13mm springs
