Size small is exactly 1.4 inch shaker balls.
https://www.amazon.com/dp/B0712156D8/ref=asc_df_B0712156D85315469/?tag=hyprod-20&creative=395033&creativeASIN=B0712156D8&linkCode=df0&hvadid=216493578477&hvpos=1o6&hvnetw=g&hvrand=11943423666353192655&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9021579&hvtargid=pla-349596846174