This is a preorder, estimated time of delivery is 2 months (~60 days) from end of preorder period.

The preorder period will last 2 weeks, will end Sunday night, November the 15th at 11:59pm est. After that, all the components will be ordered and should take about 60 days to arrive. Your orders should start shipping soon after the 60 days are up.

Ultra wide steel rail backers made from the same steel as your linear rails. These backers reinforce the crossed X and Y gantry rails, significantly increasing stiffness so you can run higher speeds and accelerations with less ringing and better surface quality. Full length of the axis with integrated mounting to the xy-joints.

By supporting the rails along their length, they reduce the effects of rail bending under load — less flex means more consistent layer heights, better dimensional accuracy, and cleaner print surfaces, especially on larger or faster prints.

Because they match the rail material, they expand and contract the same way as the rails themselves, reducing the risk of binding, uneven preload compared to dissimilar metals.

Key benefits

• Substantial increase in cross-rail stiffness
• Attaches directly to the XY Joints
• Reduced effects of rail bending on print quality (less flex, more consistent layers)
• Reduced ringing / ghosting at high speeds and accelerations
• Improved dimensional accuracy and print surface finish
• Matched steel material to the linear rails for consistent thermal behavior
• Requires a new toolhead designed for the extra clearance Hula Toolhead kit or MathematicalPotato toolhead v2

What’s included

• Hula-style steel rail backers (full set for X and Y)
• Screws for rail mounting
• Ready to install

Notes

• Designed specifically for the Annex Engineering K3 crossed-gantry rails
• Does not include rails, carriages, or toolhead parts

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Hula Toolhead kit for Annex Engineering K3

MathematicalPotato Toolhead v2 for Annex Engineering K3 Hula compatible

The backers are part of the Hula Kit:

Hula Halo for Annex Engineering K3