Classic true X 3 inch but a bit larger at 135mm

Same arms as the top mounted tiny_pulsar

Can be done 120mm by using the 2.5inch arms

https://armattanproductions.com/pages/product_details/22789

You can use a 10mm width strap for the lipo (not a fan of rubber bands for larger than 2s lipos)

It can take either a whoop board or a 16x16 stack

One extra arm

Versatile 3 inch that can be used with a single or a dual stack adding a 3d printed extension

This one has a 3mm bottom plate better suited to heavier motors like the 1407,1408 etch.

3d printed accessories here

https://www.thingiverse.com/thing:3151127

Versatile 3 inch that can be used with a single or a dual stack adding a 3d printed extension

This one has a 2mm bottom plate better suited to lighter motors like the 1106,1107,1304,1404 etch.

3d printed accessories here

https://www.thingiverse.com/thing:3151127