Turn your Stompbox 2.0 into a 2.5! The Spring Stompfin™ has been re-molded for maximum performance. Paired with a Stompbox 2.0 spring+plug, your fin will respond to impacts and rebound faster than ever!With the spacer inserted, your box will keep form under pressure and allow for smooth fin movement.The coil spring, combined with the built-in Springfin, creates the best surfing and ferrying fin that we have ever made.This Booster Kit maximizes horizontal and vertical fin stability so your fin isn't bouncing or shifting from simple water currents. Unless you are going over a rock, your fin will be held in the down position, producing maximum drive and performance for you.Please watch the videos below for installation.How to Install StompBox SpacerHow to Install the SpringFin for the Hala StompBoxBooster Includes: 2025 Spring Stompfin™ Original Stompbox 2.0 spring Spacer - keeps the spring from getting stuck over time. YES - you can use two spacers! ***Note - you may have a spring or spacer already - you may keep these as spares if you don't need them.