Similar to the thing it derives from, except this time it mounts onto a servo horn. Typically a round one of roughly 20mm in diameter. This thing allows you to mount an 'arm' onto a servo using an embedded circular servo horn. It has a total of 12 mounting holes, to match those on the servo horn, although you're likely only to use 4 of them.Material was removed from the middle in an effort to reduce the potential for warping, and to make the print time shorter. It should still have the same strength and rigidity for the typical uses of this thing.Also, instead of accomodating a 608 ball bearing, this one accepts a simple bushing on the end. This is a simpler and cheaper linkage joint.1) Print as many of these as you need 2) Mate each one to a servo horn by placing the horn inside the larger receptacle, and screwing into the horn from the outside. The opening of the horn that mates to the server should be facing outwards. 3) Slip the assembly onto the servo axle 4) Fasten to the servo axle using the tiny screw that comes with the servo horn 5) Rejoice!The lighter weight should require just that much less torque from the servo, which is a good thing.