The Nightshift is 100% 4130 chromoly throughout features super tough 41-Thermal heat-treating and comes with the proven Lifetime Warranty against bending cracking and breaking. You'll find lots of design features on the Nightshift that are comparable to the top-of-the-line Soundwave but this frame is built using traditional round tubing with unique internal gusseting for added strength.100% 4130 Chromoly FrameDouble-butted top and down tubes with proven internal gussetingPost Weld Machining: The Mid BB and Headtube is machined to its absolute minimum without sacrificing strength or durability–machining happens after welding for a precision bearing fitHollow Dropouts with Chain Tensioners: Hollow 8mm wide dropouts are as light as a solid 5mm dropout but over twice as strong. There is a small internal chain tensioner to hold the wheel in position and to simplify wheel removalRemovable Brake Hardware: removable brake mounts and cable channel improvements that provides benefits with or without a brake setupRust Proof Coating: All Sunday frames are rust-proofed with "Black Magic" coating before the final finish is applied. It is lightweight and the best anti-corrosion processing that's offered today Color Matte Sky Blue Defined Color Blue Fork Type Not Included Frame Material Steel Mfg Size 21.25 Rear Axle 14mm Threaded x 110mm TT (Effective) 21.25 Wheel Size 20" Platform Nightshift Size 21.25"