The Adventure Force Nexus Pro X Spring Tuning Spacer Set uses a series of spacers to fine-tune the performance of the Nexus Pro X with the installed spring. This set includes three full-size spacers and one half-spacer to add pre-compression to the stock spring in simple increments without tools. *WARNING: The stock Nexus Pro X spring will likely "take a set" (find a new resting state) after repeated use. Performance may differ after spring wear. *Please do not store your blaster with the spacers installed! Due to the stock pre-compression, we recommend storing the blaster without any spring installed.* FEATURES:• Nexus Pro X Spring Spacers• Set of four spring spacers• Fine-tune the performance of your Nexus Pro X• Toolless install• Designed for the Nexus Pro X• Compatible with the Aeon Pro X and select blasters with 15mm OD springs INCLUDES:• 3 Full-Size Nexus Pro X Spring Spacers• 1 Half Size Nexus Pro X Spring Spacer PERFORMANCE:Average FPS (Standard Deviation) with the stock spring and barrel• 190 (6) stock (without spacers)• 204 (2) with 1 full-size spacer• 213 (2) with 2 full-size spacers• 222 (2) with 3 full-size spacers• 228 (3) with all 4 spacers SPECS:• Material: PLA Plastic (printed in multiple colors due to this being an internal part)• Weight: .1oz • 3D-Printed LINKS:• Springs• Barrel Collet• More Nexus Pro X mods and accessories