Note:
Makeblock Socket Cap Screw will be replaced by  Button Head Socket Cap Screw gradually, and the tool HEX Screwdriver 3mm will be replaced by HEX Screwdriver 2.5mm.  
Button Head Socket Cap Screw is a new kind of Socket Cap Screw, it has smaller head that can solve most problem of interfere with other components.
 
Description:
This pack included two Fully Threaded Rods, two Linear Motion Shaft, a Universal Joint and a Thread Drive Beam.(Other beams and the motor in the last picture are not included.)
1.Fully Threaded Rod M4x192mm/M4x280mm
Features:
Made of steel, zinc plated.
Lengh: 192mm/280mm
2.Linear Motion Shaft 4x288mm
Features:
Made of tainless Steel
Can drill into 4mm holes. Compatible with Thread Drive Beam
Lengh: 288mm
3.Thread Drive Beam
Features:
Made from 6061 aluminum extrusion, anodized surface. Excellent strength and twist resistance.
With thread hole in the middle that compatible with the Fully Threaded Rod.
Other holes without thread can be drilled for 4mm shaft.
Threaded slot enables easy and flexible connection.
Cross-sectional area 8x8mm, length 80mm.
4. Universal Joint 4x4mm
Features:
Material: stainless steel
Max deflection angle: 45??
Size: D9*??4*??4*M3*L22mm
2 Headless Set Screw included.
Part list:
1x   Fully Threaded Rod M4x192mm
1x   Fully Threaded Rod M4x280mm
2x   Linear Motion Shaft 4x288mm
1x   Thread Drive Beam
1x   Universal Joint 4x4mm
2x   Headless Set Screw M3x5