These Caliburn Springs are full-length replacement main springs, offering a range of FPS options for your Captain Slug Caliburn 3 and Caliburn 4. 

FEATURES:
• Caliburn Springs
• Squared/flat on both ends for easier use
• Tune the FPS of your Caliburn

INCLUDES: 
• 1 Caliburn Spring of your choice

PERFORMANCE:
Average FPS with a 0.527 x 14in barrel
• 110 FPS with a K31 spring (280mm)
• 130 FPS with a 788 spring (266mm)
• 175 FPS with a K25 spring (280mm)
• 190 FPS with a K26 spring (280mm)

SPECS
• Material: USA-made spring-tempered steel
• Type Compression
• Dimensions:
     Spring Gauge: 1.6-2.0mm
     Length: 266mm-280mm
     Outer Diameter: 19-25mm
     Coils: varies
• Squared: Both Ends

LINKS:
• More Springs