This is a version of the MakerSlide eccentric spacer optimized for plastic carriages. It is wider (10 mm instead of 8 mm), has the bottom edges chamfered, and has a longer neck (2.9 mm instead of 1.6 mm). These features make it friendlier to soft surfaces, such as 3-D printed MakerSlide carriages. It is the same height (6.35 mm, 1/4") as the standard MakerSlide spacer, and requires the same size hole (7.14 mm, 9/32"). The inner hole is 5 mm diameter, offset 0.8 mm.
This spacer is also suitable for aluminium carriages at least 3 mm thick.