Wide compatibility for training needs: adjustable length with spacers to fit thru axle hubs from 135 mm to 148 mm, and compatible with bike frames up to 176 mm wide for use across many models. Reliable connection design: tapered heads on both ends provide a secure fit in most bike trainer mounting holes, reducing the risk of slippage during training. strength aluminum alloy material: made from 6061 aluminum alloy to withstand the rigors of intense training while maintaining structural integrity. Protective spacer design: MTB Road Bike Thru Axle Spacers conform to the shape of frame dropouts, adding protection against damage during energy workouts. Use scenario: ideal for households with mixed bike fleets (road, MTB, gravel) that use thruaxle hubs in the 135–148 mm range, with frames up to 176 mm wide, allowing a single axle solution for multiple bikes. Use scenario: supports intensity training sessions where a secure, stable connection is essential to maintain consistent pedal strokes and reduce movement. Use scenario: provides dropout protection during aggressive efforts, helping shield frame contact points from wear and impact during hard workouts.