0 Technic Pneumatic Cylinder 1 x 1 x 5.5 and Cap 0 Name: 2943ac01.dat 0 Author: Sylvain Sauvage [SLS] 0 !LDRAW_ORG Unofficial_Shortcut 0 !LICENSE Redistributable under CCAL version 2.0 : see CAreadme.txt 0 BFC CERTIFY CCW
Size: 355 bytes
Submitted by: SLS
Those are mechanical assemblies that were missing, so that users don't have to chase down and place all the parts in the complete assemblies to move the movable parts.
Okay, I confess, they are also needed for the new parts that are being added to LDD as "custom parts" now :)