MakerBeam M3 , 6mm button head socket bolts fasten beams to other MakerBeam XL elements such as brackets and bearings. Contents: bag of approximately 100 M3 button head socket bolts (6mm), used for MakerBeam XL (15mmx15mm). Compatible with OpenBeam Application: scientific, electronics, laboratories, home technical projects, displays/exhibits, robotics, etc. MakerBeam (XL) is a versatile and lightweight structural system (T-slot) with components that give endless building possibilities. There are no fixed positions for mounting giving you the freedom to build your own design easily. All MakerBeamXL elements can be combined and reused (no welding required) enabling shorter design and assembly times.